Advanced PHP – MySQL Database Connection

A cookie is often used to identify a user.


What is a Cookie?

A cookie is often used to identify a user. A cookie is a small file that the server embeds on the user’s computer. Each time the same computer requests a page with a browser, it will send the cookie too. With PHP, you can both create and retrieve cookie values.


How to Create a Cookie?

The setcookie() function is used to set a cookie.

Note: The setcookie() function must appear BEFORE the <html> tag.

Syntax

setcookie(name, value, expire, path, domain);

Example 1

In the example below, we will create a cookie named “user” and assign the value “Alex Porter” to it. We also specify that the cookie should expire after one hour:

<?php
setcookie(“user”, “Alex Porter”, time()+3600);
?>

<html>
…..

Note: The value of the cookie is automatically URLencoded when sending the cookie, and automatically decoded when received (to prevent URLencoding, use setrawcookie() instead).

Example 2

You can also set the expiration time of the cookie in another way. It may be easier than using seconds.

<?php
$expire=time()+60*60*24*30;
setcookie(“user”, “Alex Porter”, $expire);
?>

<html>
…..

In the example above the expiration time is set to a month (60 sec * 60 min * 24 hours * 30 days).


How to Retrieve a Cookie Value?

The PHP $_COOKIE variable is used to retrieve a cookie value.

In the example below, we retrieve the value of the cookie named “user” and display it on a page:

<?php
// Print a cookie
echo $_COOKIE[“user”];

// A way to view all cookies
print_r($_COOKIE);
?>

In the following example we use the isset() function to find out if a cookie has been set:

<html>
<body>

<?php
if (isset($_COOKIE[“user”]))
echo “Welcome ” . $_COOKIE[“user”] . “!<br />”;
else
echo “Welcome guest!<br />”;
?>

</body>
</html>


How to Delete a Cookie?

When deleting a cookie you should assure that the expiration date is in the past.

Delete example:

<?php
// set the expiration date to one hour ago
setcookie(“user”, “”, time()-3600);
?>


What if a Browser Does NOT Support Cookies?

If your application deals with browsers that do not support cookies, you will have to use other methods to pass information from one page to another in your application. One method is to pass the data through forms (forms and user input are described earlier in this tutorial).

The form below passes the user input to “welcome.php” when the user clicks on the “Submit” button:

<html>
<body>

<form action=”welcome.php” method=”post”>
Name: <input type=”text” name=”name” />
Age: <input type=”text” name=”age” />
<input type=”submit” />
</form>

</body>
</html>

Retrieve the values in the “welcome.php” file like this:

<html>
<body>

Welcome <?php echo $_POST[“name”]; ?>.<br />
You are <?php echo $_POST[“age”]; ?> years old.

</body>
</html>

A PHP session variable is used to store information about, or change settings for a user session. Session variables hold information about one single user, and are available to all pages in one application.


PHP Session Variables

When you are working with an application, you open it, do some changes and then you close it. This is much like a Session. The computer knows who you are. It knows when you start the application and when you end. But on the internet there is one problem: the web server does not know who you are and what you do because the HTTP address doesn’t maintain state.

A PHP session solves this problem by allowing you to store user information on the server for later use (i.e. username, shopping items, etc). However, session information is temporary and will be deleted after the user has left the website. If you need a permanent storage you may want to store the data in a database.

Sessions work by creating a unique id (UID) for each visitor and store variables based on this UID. The UID is either stored in a cookie or is propagated in the URL.


Starting a PHP Session

Before you can store user information in your PHP session, you must first start up the session.

Note: The session_start() function must appear BEFORE the <html> tag:

<?php session_start(); ?>

<html>
<body>

</body>
</html>

The code above will register the user’s session with the server, allow you to start saving user information, and assign a UID for that user’s session.


Storing a Session Variable

The correct way to store and retrieve session variables is to use the PHP $_SESSION variable:

<?php
session_start();
// store session data
$_SESSION[‘views’]=1;
?>

<html>
<body>

<?php
//retrieve session data
echo “Pageviews=”. $_SESSION[‘views’];
?>

</body>
</html>

Output:

Pageviews=1

In the example below, we create a simple page-views counter. The isset() function checks if the “views” variable has already been set. If “views” has been set, we can increment our counter. If “views” doesn’t exist, we create a “views” variable, and set it to 1:

<?php
session_start();

if(isset($_SESSION[‘views’]))
$_SESSION[‘views’]=$_SESSION[‘views’]+1;
else
$_SESSION[‘views’]=1;
echo “Views=”. $_SESSION[‘views’];
?>


Destroying a Session

If you wish to delete some session data, you can use the unset() or the session_destroy() function.

The unset() function is used to free the specified session variable:

<?php
unset($_SESSION[‘views’]);
?>

You can also completely destroy the session by calling the session_destroy() function:

<?php
session_destroy();
?>

Note: session_destroy() will reset your session and you will lose all your stored session data.

PHP allows you to send e-mails directly from a script.


The PHP mail() Function

The PHP mail() function is used to send emails from inside a script.

Syntax

mail(to,subject,message,headers,parameters)

Parameter Description
to Required. Specifies the receiver / receivers of the email
subject Required. Specifies the subject of the email. Note: This parameter cannot contain any newline characters
message Required. Defines the message to be sent. Each line should be separated with a LF (\n). Lines should not exceed 70 characters
headers Optional. Specifies additional headers, like From, Cc, and Bcc. The additional headers should be separated with a CRLF (\r\n)
parameters Optional. Specifies an additional parameter to the sendmail program

Note: For the mail functions to be available, PHP requires an installed and working email system. The program to be used is defined by the configuration settings in the php.ini file. Read more in ourPHP Mail reference.


PHP Simple E-Mail

The simplest way to send an email with PHP is to send a text email.

In the example below we first declare the variables ($to, $subject, $message, $from, $headers), then we use the variables in the mail() function to send an e-mail:

<?php
$to = “someone@example.com”;
$subject = “Test mail”;
$message = “Hello! This is a simple email message.”;
$from = “someonelse@example.com”;
$headers = “From:” . $from;
mail($to,$subject,$message,$headers);
echo “Mail Sent.”;
?>


PHP Mail Form

With PHP, you can create a feedback-form on your website. The example below sends a text message to a specified e-mail address:

<html>
<body>

<?php
if (isset($_REQUEST[’email’]))
//if “email” is filled out, send email
{
//send email
$email = $_REQUEST[’email’] ;
$subject = $_REQUEST[‘subject’] ;
$message = $_REQUEST[‘message’] ;
mail(“someone@example.com”, $subject,
$message, “From:” . $email);
echo “Thank you for using our mail form”;
}
else
//if “email” is not filled out, display the form
{
echo “<form method=’post’ action=’mailform.php’>
Email: <input name=’email’ type=’text’ /><br />
Subject: <input name=’subject’ type=’text’ /><br />
Message:<br />
<textarea name=’message’ rows=’15’ cols=’40’>
</textarea><br />
<input type=’submit’ />
</form>”;
}
?>

</body>
</html>
This is how the example above works:

  • First, check if the email input field is filled out
  • If it is not set (like when the page is first visited); output the HTML form
  • If it is set (after the form is filled out); send the email from the form
  • When submit is pressed after the form is filled out, the page reloads, sees that the email input is set, and sends the email

Note: This is the simplest way to send e-mail, but it is not secure. In the next chapter of this tutorial you can read more about vulnerabilities in e-mail scripts, and how to validate user input to make it more secure.


MySQL is the most popular open-source database system.


What is MySQL?

MySQL is a database.

The data in MySQL is stored in database objects called tables.

A table is a collection of related data entries and it consists of columns and rows.

Databases are useful when storing information categorically. A company may have a database with the following tables: “Employees”, “Products”, “Customers” and “Orders”.


Database Tables

A database most often contains one or more tables. Each table is identified by a name (e.g. “Customers” or “Orders”). Tables contain records (rows) with data.

Below is an example of a table called “Persons”:

LastName FirstName Address City
Hansen Ola Timoteivn 10 Sandnes
Svendson Tove Borgvn 23 Sandnes
Pettersen Kari Storgt 20 Stavanger

The table above contains three records (one for each person) and four columns (LastName, FirstName, Address, and City).


Queries

A query is a question or a request.

With MySQL, we can query a database for specific information and have a recordset returned.

Look at the following query:

SELECT LastName FROM Persons

The query above selects all the data in the “LastName” column from the “Persons” table, and will return a recordset like this:

LastName
Hansen
Svendson
Pettersen

Download MySQL Database

If you don’t have a PHP server with a MySQL Database, you can download MySQL for free here:http://www.mysql.com/downloads/


Facts About MySQL Database

One great thing about MySQL is that it can be scaled down to support embedded database applications. Perhaps it is because of this reputation that many people believe that MySQL can only handle small to medium-sized systems.

The truth is that MySQL is the de-facto standard database for web sites that support huge volumes of both data and end users (like Friendster, Yahoo, Google).

Look at http://www.mysql.com/customers/ for an overview of companies using MySQL.

The free MySQL database is very often used with PHP.


Create a Connection to a MySQL Database

Before you can access data in a database, you must create a connection to the database.

In PHP, this is done with the mysql_connect() function.

Syntax

mysql_connect(servername,username,password);

Parameter Description
servername Optional. Specifies the server to connect to. Default value is “localhost:3306”
username Optional. Specifies the username to log in with. Default value is the name of the user that owns the server process
password Optional. Specifies the password to log in with. Default is “”

Note: There are more available parameters, but the ones listed above are the most important. Visit our full PHP MySQL Reference for more details.

Example

In the following example we store the connection in a variable ($con) for later use in the script. The “die” part will be executed if the connection fails:

<?php
$con = mysql_connect(“localhost”,”peter”,”abc123″);
if (!$con)
{
die(‘Could not connect: ‘ . mysql_error());
}

// some code
?>


Closing a Connection

The connection will be closed automatically when the script ends. To close the connection before, use the mysql_close() function:

<?php
$con = mysql_connect(“localhost”,”peter”,”abc123″);
if (!$con)
{
die(‘Could not connect: ‘ . mysql_error());
}

// some code

mysql_close($con);
?>

Create a Database

The CREATE DATABASE statement is used to create a database in MySQL.

Syntax

CREATE DATABASE database_name
To learn more about SQL, please visit our SQL tutorial.

To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

The following example creates a database called “my_db”:

<?php
$con = mysql_connect(“localhost”,”peter”,”abc123″);
if (!$con)
{
die(‘Could not connect: ‘ . mysql_error());
}

if (mysql_query(“CREATE DATABASE my_db”,$con))
{
echo “Database created”;
}
else
{
echo “Error creating database: ” . mysql_error();
}

mysql_close($con);
?>


Create a Table

The CREATE TABLE statement is used to create a table in MySQL.

Syntax

CREATE TABLE table_name
(
column_name1 data_type,
column_name2 data_type,
column_name3 data_type,
….

)

To learn more about SQL, please visit our SQL tutorial.

We must add the CREATE TABLE statement to the mysql_query() function to execute the command.

Example

The following example creates a table named “Persons”, with three columns. The column names will be “FirstName”, “LastName” and “Age”:

<?php
$con = mysql_connect(“localhost”,”peter”,”abc123″);
if (!$con)
{
die(‘Could not connect: ‘ . mysql_error());
}

// Create database
if (mysql_query(“CREATE DATABASE my_db”,$con))
{
echo “Database created”;
}
else
{
echo “Error creating database: ” . mysql_error();
}

// Create table
mysql_select_db(“my_db”, $con);
$sql = “CREATE TABLE Persons
(
FirstName varchar(15),
LastName varchar(15),
Age int
)”;

// Execute query
mysql_query($sql,$con);

mysql_close($con);
?>

Important: A database must be selected before a table can be created. The database is selected with the mysql_select_db() function.

Note: When you create a database field of type varchar, you must specify the maximum length of the field, e.g. varchar(15).

The data type specifies what type of data the column can hold. For a complete reference of all the data types available in MySQL, go to our complete Data Types reference.


Primary Keys and Auto Increment Fields

Each table should have a primary key field.

A primary key is used to uniquely identify the rows in a table. Each primary key value must be unique within the table. Furthermore, the primary key field cannot be null because the database engine requires a value to locate the record.

The following example sets the personID field as the primary key field. The primary key field is often an ID number, and is often used with the AUTO_INCREMENT setting. AUTO_INCREMENT automatically increases the value of the field by 1 each time a new record is added. To ensure that the primary key field cannot be null, we must add the NOT NULL setting to the field.

Example

$sql = “CREATE TABLE Persons
(
personID int NOT NULL AUTO_INCREMENT,
PRIMARY KEY(personID),
FirstName varchar(15),
LastName varchar(15),
Age int
)”;

mysql_query($sql,$con);

The INSERT INTO statement is used to insert new records in a table.


Insert Data Into a Database Table

The INSERT INTO statement is used to add new records to a database table.

Syntax

It is possible to write the INSERT INTO statement in two forms.

The first form doesn’t specify the column names where the data will be inserted, only their values:

INSERT INTO table_name
VALUES (value1, value2, value3,…)

The second form specifies both the column names and the values to be inserted:

INSERT INTO table_name (column1, column2, column3,…)
VALUES (value1, value2, value3,…)
To learn more about SQL, please visit our SQL tutorial.

To get PHP to execute the statements above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

In the previous chapter we created a table named “Persons”, with three columns; “Firstname”, “Lastname” and “Age”. We will use the same table in this example. The following example adds two new records to the “Persons” table:

<?php
$con = mysql_connect(“localhost”,”peter”,”abc123″);
if (!$con)
{
die(‘Could not connect: ‘ . mysql_error());
}

mysql_select_db(“my_db”, $con);

mysql_query(“INSERT INTO Persons (FirstName, LastName, Age)
VALUES (‘Peter’, ‘Griffin’,35)”);

mysql_query(“INSERT INTO Persons (FirstName, LastName, Age)
VALUES (‘Glenn’, ‘Quagmire’,33)”);

mysql_close($con);
?>


Insert Data From a Form Into a Database

Now we will create an HTML form that can be used to add new records to the “Persons” table.

Here is the HTML form:

<html>
<body>

<form action=”insert.php” method=”post”>
Firstname: <input type=”text” name=”firstname” />
Lastname: <input type=”text” name=”lastname” />
Age: <input type=”text” name=”age” />
<input type=”submit” />
</form>

</body>
</html>

When a user clicks the submit button in the HTML form in the example above, the form data is sent to “insert.php”.

The “insert.php” file connects to a database, and retrieves the values from the form with the PHP $_POST variables.

Then, the mysql_query() function executes the INSERT INTO statement, and a new record will be added to the “Persons” table.

Here is the “insert.php” page:

<?php
$con = mysql_connect(“localhost”,”peter”,”abc123″);
if (!$con)
{
die(‘Could not connect: ‘ . mysql_error());
}

mysql_select_db(“my_db”, $con);

$sql=”INSERT INTO Persons (FirstName, LastName, Age)
VALUES
(‘$_POST[firstname]’,’$_POST[lastname]’,’$_POST[age]’)”;

if (!mysql_query($sql,$con))
{
die(‘Error: ‘ . mysql_error());
}
echo “1 record added”;

mysql_close($con);
?>

The SELECT statement is used to select data from a database.


Select Data From a Database Table

The SELECT statement is used to select data from a database.

Syntax

SELECT column_name(s)
FROM table_name

To learn more about SQL, please visit our SQL tutorial.

To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

The following example selects all the data stored in the “Persons” table (The * character selects all the data in the table):

<?php
$con = mysql_connect(“localhost”,”peter”,”abc123″);
if (!$con)
{
die(‘Could not connect: ‘ . mysql_error());
}

mysql_select_db(“my_db”, $con);

$result = mysql_query(“SELECT * FROM Persons”);

while($row = mysql_fetch_array($result))
{
echo $row[‘FirstName’] . ” ” . $row[‘LastName’];
echo “<br />”;
}

mysql_close($con);
?>

The example above stores the data returned by the mysql_query() function in the $result variable.

Next, we use the mysql_fetch_array() function to return the first row from the recordset as an array. Each call to mysql_fetch_array() returns the next row in the recordset. The while loop loops through all the records in the recordset. To print the value of each row, we use the PHP $row variable ($row[‘FirstName’] and $row[‘LastName’]).

The output of the code above will be:

Peter Griffin
Glenn Quagmire


Display the Result in an HTML Table

The following example selects the same data as the example above, but will display the data in an HTML table:

<?php
$con = mysql_connect(“localhost”,”peter”,”abc123″);
if (!$con)
{
die(‘Could not connect: ‘ . mysql_error());
}

mysql_select_db(“my_db”, $con);

$result = mysql_query(“SELECT * FROM Persons”);

echo <table border=’1′>
<
tr>
<th>Firstname</th>
<th>Lastname</th>
</tr>”;

while($row = mysql_fetch_array($result))
{
echo “<tr>”;
echo “<td>” . $row[‘FirstName’] . “</td>”;
echo “<td>” . $row[‘LastName’] . “</td>”;
echo “</tr>”;
}
echo “</table>”;

mysql_close($con);
?>

The output of the code above will be:

Firstname

Lastname

Glenn Quagmire
Peter Griffin

The WHERE clause

The WHERE clause is used to extract only those records that fulfill a specified criterion.

Syntax

SELECT column_name(s)
FROM table_name
WHERE column_name operator value

To learn more about SQL, please visit our SQL tutorial.

To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

The following example selects all rows from the “Persons” table where “FirstName=’Peter'”:

<?php
$con = mysql_connect(“localhost”,”peter”,”abc123″);
if (!$con)
{
die(‘Could not connect: ‘ . mysql_error());
}

mysql_select_db(“my_db”, $con);

$result = mysql_query(“SELECT * FROM Persons
WHERE FirstName=’Peter'”);

while($row = mysql_fetch_array($result))
{
echo $row[‘FirstName’] . ” ” . $row[‘LastName’];
echo “<br />”;
}
?>

The output of the code above will be:

Peter Griffin

The ORDER BY keyword is used to sort the data in a recordset.


The ORDER BY Keyword

The ORDER BY keyword is used to sort the data in a recordset.

The ORDER BY keyword sort the records in ascending order by default.

If you want to sort the records in a descending order, you can use the DESC keyword.

Syntax

SELECT column_name(s)
FROM table_name
ORDER BY column_name(s) ASC|DESC

To learn more about SQL, please visit our SQL tutorial.

Example

The following example selects all the data stored in the “Persons” table, and sorts the result by the “Age” column:

<?php
$con = mysql_connect(“localhost”,”peter”,”abc123″);
if (!$con)
{
die(‘Could not connect: ‘ . mysql_error());
}

mysql_select_db(“my_db”, $con);

$result = mysql_query(“SELECT * FROM Persons ORDER BY age”);

while($row = mysql_fetch_array($result))
{
echo $row[‘FirstName’];
echo ” ” . $row[‘LastName’];
echo ” ” . $row[‘Age’];
echo “<br />”;
}

mysql_close($con);
?>

The output of the code above will be:

Glenn Quagmire 33
Peter Griffin 35


Order by Two Columns

It is also possible to order by more than one column. When ordering by more than one column, the second column is only used if the values in the first column are equal:

SELECT column_name(s)
FROM table_name
ORDER BY column1, column2

The UPDATE statement is used to modify data in a table.


Update Data In a Database

The UPDATE statement is used to update existing records in a table.

Syntax

UPDATE table_name
SET column1=value, column2=value2,…
WHERE some_column=some_value
Note: Notice the WHERE clause in the UPDATE syntax. The WHERE clause specifies which record or records that should be updated. If you omit the WHERE clause, all records will be updated!

To learn more about SQL, please visit our SQL tutorial.

To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

Earlier in the tutorial we created a table named “Persons”. Here is how it looks:

FirstName LastName Age
Peter Griffin 35
Glenn Quagmire 33

The following example updates some data in the “Persons” table:

<?php
$con = mysql_connect(“localhost”,”peter”,”abc123″);
if (!$con)
{
die(‘Could not connect: ‘ . mysql_error());
}

mysql_select_db(“my_db”, $con);

mysql_query(“UPDATE Persons SET Age=36
WHERE FirstName=’Peter’ AND LastName=’Griffin'”);

mysql_close($con);
?>

After the update, the “Persons” table will look like this:

FirstName LastName Age
Peter Griffin 36
Glenn Quagmire 33

The DELETE statement is used to delete records in a table.


Delete Data In a Database

The DELETE FROM statement is used to delete records from a database table.

Syntax

DELETE FROM table_name
WHERE some_column = some_value
Note: Notice the WHERE clause in the DELETE syntax. The WHERE clause specifies which record or records that should be deleted. If you omit the WHERE clause, all records will be deleted!

To learn more about SQL, please visit our SQL tutorial.

To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

Look at the following “Persons” table:

FirstName LastName Age
Peter Griffin 35
Glenn Quagmire 33

The following example deletes all the records in the “Persons” table where LastName=’Griffin’:

<?php
$con = mysql_connect(“localhost”,”peter”,”abc123″);
if (!$con)
{
die(‘Could not connect: ‘ . mysql_error());
}

mysql_select_db(“my_db”, $con);

mysql_query(“DELETE FROM Persons WHERE LastName=’Griffin'”);

mysql_close($con);
?>

After the deletion, the table will look like this:

FirstName LastName Age
Glenn Quagmire 33

Create an ODBC Connection

With an ODBC connection, you can connect to any database, on any computer in your network, as long as an ODBC connection is available.

Here is how to create an ODBC connection to a MS Access Database:

  1. Open the Administrative Tools icon in your Control Panel.
  2. Double-click on the Data Sources (ODBC) icon inside.
  3. Choose the System DSN tab.
  4. Click on Add in the System DSN tab.
  5. Select the Microsoft Access Driver. Click Finish.
  6. In the next screen, click Select to locate the database.
  7. Give the database a Data Source Name (DSN).
  8. Click OK.

Note that this configuration has to be done on the computer where your web site is located. If you are running Internet Information Server (IIS) on your own computer, the instructions above will work, but if your web site is located on a remote server, you have to have physical access to that server, or ask your web host to to set up a DSN for you to use.


Connecting to an ODBC

The odbc_connect() function is used to connect to an ODBC data source. The function takes four parameters: the data source name, username, password, and an optional cursor type.

The odbc_exec() function is used to execute an SQL statement.

Example

The following example creates a connection to a DSN called northwind, with no username and no password. It then creates an SQL and executes it:

$conn=odbc_connect(‘northwind’,”,”);
$sql=”SELECT * FROM customers”;
$rs=odbc_exec($conn,$sql);


Retrieving Records

The odbc_fetch_row() function is used to return records from the result-set. This function returns true if it is able to return rows, otherwise false.

The function takes two parameters: the ODBC result identifier and an optional row number:

odbc_fetch_row($rs)


Retrieving Fields from a Record

The odbc_result() function is used to read fields from a record. This function takes two parameters: the ODBC result identifier and a field number or name.

The code line below returns the value of the first field from the record:

$compname=odbc_result($rs,1);

The code line below returns the value of a field called “CompanyName”:

$compname=odbc_result($rs,”CompanyName”);


Closing an ODBC Connection

The odbc_close() function is used to close an ODBC connection.

odbc_close($conn);


An ODBC Example

The following example shows how to first create a database connection, then a result-set, and then display the data in an HTML table.

<html>
<body>

<?php
$conn=odbc_connect(‘northwind’,”,”);
if (!$conn)
{exit(“Connection Failed: ” . $conn);}
$sql=”SELECT * FROM customers”;
$rs=odbc_exec($conn,$sql);
if (!$rs)
{exit(“Error in SQL”);}
echo “<table><tr>”;
echo “<th>Companyname</th>”;
echo “<th>Contactname</th></tr>”;
while (odbc_fetch_row($rs))
{
$compname=odbc_result($rs,”CompanyName”);
$conname=odbc_result($rs,”ContactName”);
echo “<tr><td>$compname</td>”;
echo “<td>$conname</td></tr>”;
}
odbc_close($conn);
echo “</table>”;
?>

</body>
</html>

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PHP – For Beginners

PHP is a powerful tool for making dynamic and interactive Web pages.

What You Should Already Know
Before you continue you should have a basic understanding of the following:

  • HTML/XHTML
  • JavaScrit

PHP is the widely-used, free, and efficient alternative to competitors such as Microsoft’s ASP.

PHP is a widely-used general-purpose scripting language that is especially suited for Web development and can be embedded into HTML.

PHP (recursive acronym for PHP: Hypertext Preprocessor) is a widely-used open source general-purpose scripting language that is especially suited for web development and can be embedded into HTML.

PHP is a server-side scripting language.


PHP stands for PHP: Hypertext Preprocessor

  • PHP is a server-side scripting language, like ASP
  • PHP scripts are executed on the server
  • PHP supports many databases (MySQL, Informix, Oracle, Sybase, Solid, PostgreSQL, Generic ODBC, etc.)
  • PHP is an open source software
  • PHP is free to download and use

What is a PHP File?

  • PHP files can contain text, HTML tags and scripts
  • PHP files are returned to the browser as plain HTML
  • PHP files have a file extension of “.php”, “.php3”, or “.phtml”

What is MySQL?

  • MySQL is a database server
  • MySQL is ideal for both small and large applications
  • MySQL supports standard SQL
  • MySQL compiles on a number of platforms
  • MySQL is free to download and use

PHP + MySQL

  • PHP combined with MySQL are cross-platform (you can develop in Windows and serve on a Unix platform)

Why PHP?

  • PHP runs on different platforms (Windows, Linux, Unix, etc.)
  • PHP is compatible with almost all servers used today (Apache, IIS, etc.)
  • PHP is FREE to download from the official PHP resource: www.php.net
  • PHP is easy to learn and runs efficiently on the server side

Where to Start?

To get access to a web server with PHP support, you can:

  • Install Apache (or IIS) on your own server, install PHP, and MySQL
  • Or find a web hosting plan with PHP and MySQL support

What do you Need?

If your server supports PHP you don’t need to do anything. Just create some .php files in your web directory, and the server will parse them for you. Because it is free, most web hosts offer PHP support.

However, if your server does not support PHP, you must install PHP.

Here is a link to a good tutorial from PHP.net on how to install PHP5:         http://www.php.net/manual/en/install.php

Download PHP

Download PHP for free here: http://www.php.net/downloads.php

Download MySQL Database

Download MySQL for free here: http://www.mysql.com/downloads/

Download Apache Server

Download Apache for free here: http://httpd.apache.org/download.cgi

The PHP script is executed on the server, and the plain HTML result is sent back to the browser.


Basic PHP Syntax

A PHP script always starts with <?php and ends with ?>. A PHP script can be placed anywhere in the document. On servers with shorthand-support, you can start a PHP script with <? and end with ?>. For maximum compatibility, we recommend that you use the standard form (<?php) rather than the shorthand form.

<?php
?>

A PHP file must have a .php extension.

A PHP file normally contains HTML tags, and some PHP scripting code. Below, we have an example of a simple PHP script that sends the text “Hello World” back to the browser:

<html>
<body>
<?php
echo “Hello World”;
?>
</body>
</html>

 

Each code line in PHP must end with a semicolon. The semicolon is a separator and is used to distinguish one set of instructions from another.

There are two basic statements to output text with PHP: echo and print.

In the example above we have used the echo statement to output the text “Hello World”.


Comments in PHP

In PHP, we use // to make a one-line comment or /* and */ to make a comment block:

<html>
<body>
<?php
//This is a comment
/*
This is
a comment
block
*/
?>
</body>
</html>

Variables are “containers” for storing information.


Do You Remember Algebra From School?

Do you remember algebra from school? x=5, y=6, z=x+y

Do you remember that a letter (like x) could be used to hold a value (like 5), and that you could use the information above to calculate the value of z to be 11?

These letters are called variables, and variables can be used to hold values (x=5) or expressions (z=x+y).


PHP Variables

As with algebra, PHP variables are used to hold values or expressions.

A variable can have a short name, like x, or a more descriptive name, like carName.

Rules for PHP variable names:

  • Variables in PHP starts with a $ sign, followed by the name of the variable
  • The variable name must begin with a letter or the underscore character
  • A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )
  • A variable name should not contain spaces
  • Variable names are case sensitive (y and Y are two different variables

Creating (Declaring) PHP Variables

PHP has no command for declaring a variable. A variable is created the moment you first assign a value to it:

$myCar=”Volvo”;

After the execution of the statement above, the variable myCar will hold the value Volvo.

Tip: If you want to create a variable without assigning it a value, then you assign it the value of null.

Let’s create a variable containing a string, and a variable containing a number:

<?php
$txt=”Hello World!”;
$x=16;
?>

Note: When you assign a text value to a variable, put quotes around the value.


PHP is a Loosely Typed Language

In PHP, a variable does not need to be declared before adding a value to it. In the example above, notice that we did not have to tell PHP which data type the variable is. PHP automatically converts the variable to the correct data type, depending on its value. In a strongly typed programming language, you have to declare (define) the type and name of the variable before using it.


PHP Variable Scope

The scope of a variable is the portion of the script in which the variable can be referenced.

PHP has four different variable scopes:

  • local
  • global
  • static
  • parameter

Local Scope

A variable declared within a PHP function becomes local and can only be accessed within that function. (the variable has local scope).

You can have local variables with the same name in different functions, because local variables are only recognized by the function in which they are declared. Local variables are deleted as soon as the function is completed.


Global Scope

Global scope refers to any variable that is defined outside of any function. Global variables can be accessed from   any part of the program that is not inside a function. To access a global variable from within a function, use the global keyword:

<?php
$a = 10; // global scope
function myTest()
{
echo global $a; // reference to global scope variable
}
myTest();
?>

 

PHP also stores all global variables in an array called $GLOBALS[ ]. Its index is the name of the variable. This array is also accessible from within functions and can be used to update global variables directly:

global $a;
$a=”abc”;
// is the same as
$GLOBALS[“a”]=”abc”;

Static Scope

When a function is completed, all of its variables are normally deleted. However, sometimes you want a local variable to not be deleted.

To do this, use the static keyword when you first declare the variable:

static $rememberMe;

Then, each time the function is called, that variable will still have the information it contained from the last time the function was called.

Note: The variable is still local to the function.


Parameters

A parameter is a local variable whose value is passed to the function by the calling code. Parameters are declared in a parameter list as part of the function declaration:

function myTest($para1,$para2,…)
{
// function code
}

Parameters are also called arguments. We will discuss them in more detail when we talk about functions.

A string variable is used to store and manipulate text.


String Variables in PHP

String variables are used for values that contain characters. In this chapter we are going to look at the most common functions and operators used to manipulate strings in PHP. After we create a string we can manipulate it. A string can be used directly in a function or it can be stored in a variable.

Below, the PHP script assigns the text “Hello World” to a string variable called $txt:

<?php
$txt=”Hello World”;
echo $txt;
?>

The output of the code above will be:

Hello World

Now, lets try to use some different functions and operators to manipulate the string.


The Concatenation Operator

There is only one string operator in PHP.

The concatenation operator (.)  is used to put two string values together. To concatenate two string variables together, use the concatenation operator:

<?php
$txt1=”Hello World!”;
$txt2=”What a nice day!”;
echo $txt1 . ” ” . $txt2;
?>

The output of the code above will be:

Hello World! What a nice day!

If we look at the code above you see that we used the concatenation operator two times. This is because we had to insert a third string (a space character), to separate the two strings.


The strlen() function

The strlen() function is used to return the length of a string. Let’s find the length of a string:

<?php
echo strlen(“Hello world!”);
?>

The output of the code above will be:

12

The length of a string is often used in loops or other functions, when it is important to know when the string ends. (i.e. in a loop, we would want to stop the loop after the last character in the string).

The strpos() function

The strpos() function is used to search for a character/text within a string.

If a match is found, this function will return the character position of the first match. If no match is found, it will return FALSE.

Let’s see if we can find the string “world” in our string:

<?php
echo strpos(“Hello world!”,”world”);
?>

The output of the code above will be:

6

The position of the string “world” in the example above is 6. The reason that it is 6 (and not 7), is that the first character position in the string is 0, and not 1.

Complete PHP String Reference

For a complete reference of all string functions, go to our complete PHP String Reference. The reference contains a brief description, and examples of use, for each function!

The assignment operator = is used to assign values to variables in PHP. The arithmetic operator + is used to add values together.


Arithmetic Operators

The table below lists the arithmetic operators in PHP:

Operator Name Description Example Result
x + y Addition Sum of x and y 2 + 2 4
x – y Subtraction Difference of x and y 5 – 2 3
x * y Multiplication Product of x and y 5 * 2 10
x / y Division Quotient of x and y 15 / 5 3
x % y Modulus Remainder of x divided by y 5 % 2
10 % 8
10 % 2
1
2
0
– x Negation Opposite of x – 2
a . b Concatenation Concatenate two strings “Hi” . “Ha” HiHa

Assignment Operators

The basic assignment operator in PHP is “=”. It means that the left operand gets set to the value of the expression on the right. That is, the value of “$x = 5” is 5.

Assignment Same as… Description
x = y x = y The left operand gets set to the value of the expression on the right
x += y x = x + y Addition
x -= y x = x – y Subtraction
x *= y x = x * y Multiplication
x /= y x = x / y Division
x %= y x = x % y Modulus
a .= b a = a . b Concatenate two strings

Incrementing/Decrementing Operators

Operator Name Description
++ x Pre-increment Increments x by one, then returns x
x ++ Post-increment Returns x, then increments x by one
— x Pre-decrement Decrements x by one, then returns x
x — Post-decrement Returns x, then decrements x by one

Comparison Operators

Comparison operators allow you to compare two values:

Operator Name Description Example
x == y Equal True if x is equal to y 5==8 returns false
x === y Identical True if x is equal to y, and they are of same type 5===”5″ returns false
x != y Not equal True if x is not equal to y 5!=8 returns true
x <> y Not equal True if x is not equal to y 5<>8 returns true
x !== y Not identical True if x is not equal to y, or they are not of same type 5!==”5″ returns true
x > y Greater than True if x is greater than y 5>8 returns false
x < y Less than True if x is less than y 5<8 returns true
x >= y Greater than or equal to True if x is greater than or equal to y 5>=8 returns false
x <= y Less than or equal to True if x is less than or equal to y 5<=8 returns true

Logical Operators

Operator Name Description Example
x and y And True if both x and y are true x=6
y=3
(x < 10 and y > 1) returns true
x or y Or True if either or both x and y are true x=6
y=3
(x==6 or y==5) returns true
x xor y Xor True if either x or y is true, but not both x=6
y=3
(x==6 xor y==3) returns false
x && y And True if both x and y are true x=6
y=3
(x < 10 && y > 1) returns true
x || y Or True if either or both x and y are true x=6
y=3
(x==5 || y==5) returns false
! x Not True if x is not true x=6
y=3
!(x==y) returns true

Array Operators

Operator Name Description
x + y Union Union of x and y
x == y Equality True if x and y have the same key/value pairs
x === y Identity True if x and y have the same key/value pairs in the same order and of the same types
x != y Inequality True if x is not equal to y
x <> y Inequality True if x is not equal to y
x !== y Non-identity True if x is not identical to y

Conditional statements are used to perform different actions based on different conditions.


Conditional Statements

Very often when you write code, you want to perform different actions for different decisions. You can use conditional statements in your code to do this.  In PHP we have the following conditional statements:

  • if statement – use this statement to execute some code only if a specified condition is true
  • if…else statement – use this statement to execute some code if a condition is true and another code if the condition is false
  • if…elseif….else statement – use this statement to select one of several blocks of code to be executed
  • switch statement – use this statement to select one of many blocks of code to be executed

The if Statement

Use the if statement to execute some code only if a specified condition is true.

Syntax

if (conditioncode to be executed if condition is true;

The following example will output “Have a nice weekend!” if the current day is Friday:

<html>
<body>
<?php
$d=date(“D”);
if ($d==”Fri”) echo “Have a nice weekend!”;
?>
</body>
</html>

Notice that there is no ..else.. in this syntax. The code is executed only if the specified condition is true.


The if…else Statement

Use the if….else statement to execute some code if a condition is true and another code if a condition is false.

Syntax

if (condition)
code to be executed if condition is true;
else
code to be executed if condition is false;

Example

The following example will output “Have a nice weekend!” if the current day is Friday, otherwise it will output “Have a nice day!”:

<html>
<body>
<?php
$d=date(“D”);
if ($d==”Fri”)
echo “Have a nice weekend!”;
else
echo “Have a nice day!”;
?>

</body>
</html>

If more than one line should be executed if a condition is true/false, the lines should be enclosed within curly braces:

<html>
<body>
<?php
$d=date(“D”);
if ($d==”Fri”)
{
echo “Hello!<br />”;
echo “Have a nice weekend!”;
echo “See you on Monday!”;
}
?>
</body>
</html>


The if…elseif….else Statement

Use the if….elseif…else statement to select one of several blocks of code to be executed.

Syntax

if (condition)
code to be executed if condition is true;
elseif (condition)
code to be executed if condition is true;
else
code to be executed if condition is false;

Example

The following example will output “Have a nice weekend!” if the current day is Friday, and “Have a nice Sunday!” if the current day is Sunday. Otherwise it will output “Have a nice day!”:

<html>
<body>

<?php
$d=date(“D”);
if ($d==”Fri”)
echo “Have a nice weekend!”;
elseif ($d==”Sun”)
echo “Have a nice Sunday!”;
else
echo “Have a nice day!”;
?>

</body>
</html>

Conditional statements are used to perform different actions based on different conditions.


The PHP Switch Statement

Use the switch statement to select one of many blocks of code to be executed.

Syntax

switch (n)
{
case label1:
code to be executed if n=label1;
break;
case label2:
code to be executed if n=label2;
break;
default:
code to be executed if n is different from both label1 and label2;
}

This is how it works: First we have a single expression n (most often a variable), that is evaluated once. The value of the expression is then compared with the values for each case in the structure. If there is a match, the block of code associated with that case is executed. Use break to prevent the code from running into the next case automatically. The default statement is used if no match is found.

Example

<html>
<body>

<?php
$x=1;
switch ($x)
{
case 1:
echo “Number 1”;
break;
case 2:
echo “Number 2”;
break;
case 3:
echo “Number 3”;
break;
default:
echo “No number between 1 and 3”;
}
?>

</body>
</html>

An array stores multiple values in one single variable.


What is an Array?

A variable is a storage area holding a number or text. The problem is, a variable will hold only one value.

An array is a special variable, which can store multiple values in one single variable.

If you have a list of items (a list of car names, for example), storing the cars in single variables could look like this:

$cars1=”Saab”;
$cars2=”Volvo”;
$cars3=”BMW”;

However, what if you want to loop through the cars and find a specific one? And what if you had not 3 cars, but 300?

The best solution here is to use an array!

An array can hold all your variable values under a single name. And you can access the values by referring to the array name.

Each element in the array has its own index so that it can be easily accessed.

In PHP, there are three kind of arrays:

  • Numeric array – An array with a numeric index
  • Associative array – An array where each ID key is associated with a value
  • Multidimensional array – An array containing one or more arrays

Numeric Arrays

A numeric array stores each array element with a numeric index. There are two methods to create a numeric array.

1. In the following example the index are automatically assigned (the index starts at 0):

$cars=array(“Saab”,”Volvo”,”BMW”,”Toyota”);

2. In the following example we assign the index manually:

$cars[0]=”Saab”;
$cars[1]=”Volvo”;
$cars[2]=”BMW”;
$cars[3]=”Toyota”;

Example

In the following example you access the variable values by referring to the array name and index:

<?php
$cars[0]=”Saab”;
$cars[1]=”Volvo”;
$cars[2]=”BMW”;
$cars[3]=”Toyota”;
echo $cars[0] . ” and ” . $cars[1] . ” are Swedish cars.”;
?>

The code above will output:

Saab and Volvo are Swedish cars.


Associative Arrays

An associative array, each ID key is associated with a value. When storing data about specific named values, a numerical array is not always the best way to do it. With associative arrays we can use the values as keys and assign values to them.

Example 1

In this example we use an array to assign ages to the different persons:

$ages = array(“Peter”=>32, “Quagmire”=>30, “Joe”=>34);

Example 2

This example is the same as example 1, but shows a different way of creating the array:

$ages[‘Peter’] = “32”;
$ages[‘Quagmire’] = “30”;
$ages[‘Joe’] = “34”;

The ID keys can be used in a script:

<?php
$ages[‘Peter’] = “32”;
$ages[‘Quagmire’] = “30”;
$ages[‘Joe’] = “34”;

echo “Peter is ” . $ages[‘Peter’] . ” years old.”;
?>

The code above will output:

Peter is 32 years old.


Multidimensional Arrays

In a multidimensional array, each element in the main array can also be an array. And each element in the sub-array can be an array, and so on.

Example

In this example we create a multidimensional array, with automatically assigned ID keys:

$families = array
(
“Griffin”=>array
(
“Peter”,
“Lois”,
“Megan”
),
“Quagmire”=>array
(
“Glenn”
),
“Brown”=>array
(
“Cleveland”,
“Loretta”,
“Junior”
)
);

The array above would look like this if written to the output:

Array
(
[Griffin] => Array
(
[0] => Peter
[1] => Lois
[2] => Megan
)
[Quagmire] => Array
(
[0] => Glenn
)
[Brown] => Array
(
[0] => Cleveland
[1] => Loretta
[2] => Junior
)
)

Example 2

Lets try displaying a single value from the array above:

echo “Is ” . $families[‘Griffin’][2] .
” a part of the Griffin family?”;

The code above will output:

Is Megan a part of the Griffin family?


Complete PHP Array Reference

For a complete reference of all array functions, go to our complete PHP Array Reference.

The reference contains a brief description, and examples of use, for each function!

Loops execute a block of code a specified number of times, or while a specified condition is true.


PHP Loops

Often when you write code, you want the same block of code to run over and over again in a row. Instead of adding several almost equal lines in a script we can use loops to perform a task like this.

In PHP, we have the following looping statements:

  • while – loops through a block of code while a specified condition is true
  • do…while – loops through a block of code once, and then repeats the loop as long as a specified condition is true
  • for – loops through a block of code a specified number of times
  • foreach – loops through a block of code for each element in an array

The while Loop

The while loop executes a block of code while a condition is true.

Syntax

while (condition)
{
  code to be executed;
}

Example

The example below defines a loop that starts with i=1. The loop will continue to run as long as i is less than, or equal to 5. i will increase by 1 each time the loop runs:

<html>
<body>
<?php
$i=1;
while($i<=5)
{
echo “The number is ” . $i . “<br />”;
$i++;
}
?>

</body>
</html>

Output:

The number is 1
The number is 2
The number is 3
The number is 4
The number is 5


The do…while Statement

The do…while statement will always execute the block of code once, it will then check the condition, and repeat the loop while the condition is true.

Syntax

do
{
code to be executed;
}
while (condition);

Example

The example below defines a loop that starts with i=1. It will then increment i with 1, and write some output. Then the condition is checked, and the loop will continue to run as long as i is less than, or equal to 5:

<html>
<body>
<?php
$i=1;
do
{
$i++;
echo “The number is ” . $i . “<br />”;
}
while ($i<=5);
?>

</body>
</html>

Output:

The number is 2
The number is 3
The number is 4
The number is 5
The number is 6

The for loop and the foreach loop will be explained in the next chapter.

Loops execute a block of code a specified number of times, or while a specified condition is true.


The for Loop

The for loop is used when you know in advance how many times the script should run.

Syntax

for (init; condition; increment)
{
code to be executed;
}

Parameters:

  • init: Mostly used to set a counter (but can be any code to be executed once at the beginning of the loop)
  • condition: Evaluated for each loop iteration. If it evaluates to TRUE, the loop continues. If it evaluates to FALSE, the loop ends.
  • increment: Mostly used to increment a counter (but can be any code to be executed at the end of the iteration)

Note: The init and increment parameters above can be empty or have multiple expressions (separated by commas).

Example

The example below defines a loop that starts with i=1. The loop will continue to run as long as i is less than, or equal to 5. i will increase by 1 each time the loop runs:

<html>
<body>
<?php
for ($i=1; $i<=5; $i++)
{
echo “The number is ” . $i . “<br />”;
}
?>
</body>
</html>

Output:

The number is 1
The number is 2
The number is 3
The number is 4
The number is 5


The foreach Loop

The foreach loop is used to loop through arrays.

Syntax

foreach ($array as $value)
{
code to be executed;
}

For every loop iteration, the value of the current array element is assigned to $value (and the array pointer is moved by one) – so on the next loop iteration, you’ll be looking at the next array value.

Example

The following example demonstrates a loop that will print the values of the given array:

<html>
<body>
<?php
$x=array(“one”,”two”,”three”);
foreach ($x as $value)
{
echo $value . “<br />”;
}
?>
</body>
</html>

Output:

one
two
three

The real power of PHP comes from its functions. In PHP, there are more than 700 built-in functions.


PHP Built-in Functions

For a complete reference and examples of the built-in functions, please visit our PHP Reference.


PHP Functions

In this chapter we will show you how to create your own functions. To keep the script from being executed when the page loads, you can put it into a function. A function will be executed by a call to the function.

You may call a function from anywhere within a page.


Create a PHP Function

A function will be executed by a call to the function.

Syntax

function functionName()
{
code to be executed;
}

PHP function guidelines:

  • Give the function a name that reflects what the function does
  • The function name can start with a letter or underscore (not a number)

Example

A simple function that writes my name when it is called:
<html>
<body>
<?php
function writeName()
{
echo “Kai Jim Refsnes”;
}
echo “My name is “;
writeName();
?>
</body>
</html>

Output:
My name is Kai Jim Refsnes


PHP Functions – Adding parameters

To add more functionality to a function, we can add parameters. A parameter is just like a variable. Parameters are specified after the function name, inside the parentheses.

Example 1
The following example will write different first names, but equal last name:

<html>
<body>

<?php
function writeName($fname)
{
echo $fname . ” Refsnes.<br />”;
}
echo “My name is “;
writeName(“Kai Jim”);
echo “My sister’s name is “;
writeName(“Hege”);
echo “My brother’s name is “;
writeName(“Stale”);
?>
</body>
</html>

Output:

My name is Kai Jim Refsnes.
My sister’s name is Hege Refsnes.
My brother’s name is Stale Refsnes.

Example 2

The following function has two parameters:

<html>
<body>
<?php
function writeName($fname,$punctuation)
{
echo $fname . ” Refsnes” . $punctuation . “<br />”;
}
echo “My name is “;
writeName(“Kai Jim”,”.”);
echo “My sister’s name is “;
writeName(“Hege”,”!”);
echo “My brother’s name is “;
writeName(“Ståle”,”?”);
?>
</body>
</html>

Output:

My name is Kai Jim Refsnes.
My sister’s name is Hege Refsnes!
My brother’s name is Ståle Refsnes?


PHP Functions – Return values

To let a function return a value, use the return statement.

Example

<html>
<body>
<?php
function add($x,$y)
{
$total=$x+$y;
return $total;
}
echo “1 + 16 = ” . add(1,16);
?>
</body>
</html>

Output:

1 + 16 = 17

The PHP $_GET and $_POST variables are used to retrieve information from forms, like user input.


PHP Form Handling

The most important thing to notice when dealing with HTML forms and PHP is that any form element in an HTML page will automatically be available to your PHP scripts.

Example

The example below contains an HTML form with two input fields and a submit button:

<html>
<body>
<form action=”welcome.php” method=”post”>
Name: <input type=”text” name=”fname” />
Age: <input type=”text” name=”age” />
<input type=”submit” />
</form>
</body>
</html>

When a user fills out the form above and click on the submit button, the form data is sent to a PHP file, called “welcome.php”:

“welcome.php” looks like this:

<html>
<body>
Welcome <?php echo $_POST[“fname”]; ?>!<br />
You are <?php echo $_POST[“age”]; ?> years old.
</body>
</html>

Output could be something like this:

Welcome John!
You are 28 years old.

The PHP $_GET and $_POST variables will be explained in the next chapters.


Form Validation

User input should be validated on the browser whenever possible (by client scripts). Browser validation is faster and reduces the server load.

You should consider server validation if the user input will be inserted into a database. A good way to validate a form on the server is to post the form to itself, instead of jumping to a different page. The user will then get the error messages on the same page as the form. This makes it easier to discover the error.

In PHP, the predefined $_GET variable is used to collect values in a form with method=”get”.


The $_GET Variable

The predefined $_GET variable is used to collect values in a form with method=”get”

Information sent from a form with the GET method is visible to everyone (it will be displayed in the browser’s address bar) and has limits on the amount of information to send.

Example

<form action=”welcome.php” method=”get”>
Name: <input type=”text” name=”fname” />
Age: <input type=”text” name=”age” />
<input type=”submit” />
</form>

When the user clicks the “Submit” button, the URL sent to the server could look something like this:

http://www.w3schools.com/welcome.php?fname=Peter&age=37

The “welcome.php” file can now use the $_GET variable to collect form data (the names of the form fields will automatically be the keys in the $_GET array):

Welcome <?php echo $_GET[“fname”]; ?>.<br />
You are <?php echo $_GET[“age”]; ?> years old!


When to use method=”get”?

When using method=”get” in HTML forms, all variable names and values are displayed in the URL.

Note:
 This method should not be used when sending passwords or other sensitive information!
However, because the variables are displayed in the URL, it is possible to bookmark the page. This can be useful in some cases.

Note: The get method is not suitable for very large variable values. It should not be used with values exceeding 2000 characters.