Web Application Development using PHP Chapter 5

CN5109
WEB APPLICATION
DEVELOPMENT
Chapter 5
PHP Form

PHP Form
• A Form is a document that containing black fields, that the
user can fill the data or user can select the data.
• Casually the data will store in the data base.
• When the user fills out the form and clicks the submit button,
the form data is sent for processing to a PHP file.
• The form data is sent with the HTTP POST or GET method.

PHP Form
• Example PHP Form using HTML POST method:
<body>
<form action="welcome.php" method="post">
Name: <input type="text" name="name"><br>
E-mail: <input type="text" name="email"><br>
<input type="submit">
</form>
</body>

PHP Form
• To display the submitted data you could simply echo all the
variables.
• The "welcome.php" looks like this:
<body>
Welcome <?php echo $_POST["name"]; ?><br>
Your email address is: <?php echo $_POST["email"]; ?>
</body>

PHP Form
• The same result could also be achieved using the HTTP GET
method:
<body>
<form action="welcome_get.php" method="get">
Name: <input type="text" name="name"><br>
E-mail: <input type="text" name="email"><br>
<input type="submit">
</form>
</body>

PHP Form
• The "welcome_get.php" looks like this:
<body>
Welcome <?php echo $_GET["name"]; ?><br>
Your email address is: <?php echo $_GET["email"]; ?>
</body>

GET vs. POST
• Both GET and POST create an array (e.g. array( key => value,
key2 => value2, key3 => value3, ...)).
• This array holds key/value pairs, where keys are the names of
the form controls and values are the input data from the user.
• $_GET is an array of variables passed to the current script via
the URL parameters.
• $_POST is an array of variables passed to the current script via
the HTTP POST method.

GET vs. POST
• Information sent from a form with the GET method is visible
to everyone (all variable names and values are displayed in
the URL).
• GET also has limits on the amount of information to send.
• The limitation is about 2000 characters.
• GET may be used for sending non-sensitive data.

GET vs. POST
• Information sent from a form with the POST method is
invisible to others (all names/values are embedded within the
body of the HTTP request) and has no limits on the amount of
information to send.
• POST supports advanced functionality such as support for
multi-part binary input while uploading files to server.

Form Validation
• Validation means check the input submitted by the user.
• Proper validation of form data is important to protect your
form from hackers and spammers!
• There are two types of validation are available in PHP.
• They are as follows:
• Client-Side Validation − Validation is performed on the
client machine web browsers.
• Server Side Validation − After submitted by data, The
data has sent to a server and perform validation
checks in server machine.

Example
• Below code shows validation of URL:
• Below code shows validation of Email address
$website = input($_POST["site"]);
if (!preg_match("/b(?:(?:https?|ftp)://|www.)[-a-z0-
9+&@#/%?=~_|!:,.;]*[-a-z0-9+&@#/%=~_|]/i",$website))
{
$websiteErr = "Invalid URL";
}
$email = input($_POST["email"]);
if (!filter_var($email, FILTER_VALIDATE_EMAIL))
{
$emailErr = "Invalid format and please re-enter valid email";
}

Example
• The code below shows a simple way to check if the name field
only contains letters and whitespace.
• If the value of the name field is not valid, then store an error
message:
$name = test_input($_POST["name"]);
if (!preg_match("/^[a-zA-Z ]*$/",$name))
{
$nameErr = "Only letters and white space allowed";
}
preg_match – this function is used to perform a pattern match on a
string. It returns true if a match is found and false if a match is not found.

Example
• In the code below, if the e-mail address is not well-formed,
then store an error message:
$email = test_input($_POST["email"]);
if (!filter_var($email, FILTER_VALIDATE_EMAIL))
{
$emailErr = "Invalid email format";
}

Web Application Development using PHP Chapter 5

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Web Application Development using PHP Chapter 5