PHP
5 Forms - Validate E-mail and URL
PHP
- Validate Name
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";
}
The
preg_match() function searches a string for pattern, returning true if the
pattern exists, and false otherwise.
PHP
- Validate E-mail
The easiest
and safest way to check whether an email address is well-formed is to use PHP's
filter_var() function.
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";
}
PHP
- Validate URL
The code
below shows a way to check if a URL address syntax is valid (this regular
expression also allows dashes in the URL). If the URL address syntax is not
valid, then store an error message:
$website
= test_input($_POST["website"]);
if
(!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website))
{
$websiteErr = "Invalid URL";
}
PHP -
Validate Name, E-mail, and URL
Now, the
script looks like this:
Example
<?php
//
define variables and set to empty values
$nameErr
= $emailErr = $genderErr = $websiteErr = "";
$name
= $email = $gender = $comment = $website = "";
if
($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
$nameErr = "Name is required";
} else {
$name =
test_input($_POST["name"]);
// check if name only contains letters and
whitespace
if (!preg_match("/^[a-zA-Z
]*$/",$name)) {
$nameErr = "Only letters and white
space allowed";
}
}
if (empty($_POST["email"])) {
$emailErr = "Email is required";
} else {
$email =
test_input($_POST["email"]);
// check if e-mail address is well-formed
if (!filter_var($email,
FILTER_VALIDATE_EMAIL)) {
$emailErr = "Invalid email
format";
}
}
if (empty($_POST["website"])) {
$website = "";
} else {
$website =
test_input($_POST["website"]);
// check if URL address syntax is valid
(this regular expression also allows dashes in the URL)
if
(!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website))
{
$websiteErr = "Invalid URL";
}
}
if (empty($_POST["comment"])) {
$comment = "";
} else {
$comment =
test_input($_POST["comment"]);
}
if (empty($_POST["gender"])) {
$genderErr = "Gender is
required";
} else {
$gender =
test_input($_POST["gender"]);
}
}
?>
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