if ($_SERVER[“REQUEST_METHOD”] == “POST”) {
if (empty($_POST[“name”])) {
$nameError = “Name is required”;
} else {
$name = test_input($_POST[“name”]);
// check if name only contains letters and whitespace
if (!preg_match(“/^[a-zA-Z ]*$/”,$name)) {
$nameError = “Only letters and white space allowed”;
}
}

if (empty($_POST[“email”])) {
$emailError = “Email is required”;
} else {
$email = test_input($_POST[“email”]);
// check if e-mail address syntax is valid
if (!preg_match(“/([\w\-]+\@[\w\-]+\.[\w\-]+)/”,$email)) {
$emailError = “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)) {
$websiteError = “Invalid URL”;
}
}

if (empty($_POST[“comment”])) {
$comment = “”;
} else {
$comment = test_input($_POST[“comment”]);
}

if (empty($_POST[“gender”])) {
$genderError = “Gender is required”;
} else {
$gender = test_input($_POST[“gender”]);
}
}

function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>

<h2>PHP Form Validation</h2>
<p><span class=”error”>* required field.</span></p>
<form method=”post” action=”<?php echo htmlspecialchars($_SERVER[“PHP_SELF”]);?>“> 
   Name: <input type=”text” name=”name”>
   <span class=”error”>* <?php echo $nameError;?></span>
   <br><br>
   E-mail: <input type=”text” name=”email”>
   <span class=”error”>* <?php echo $emailError;?></span>
   <br><br>
   Website: <input type=”text” name=”website”>
   <span class=”error”><?php echo $websiteError;?></span>
   <br><br>
   Comment: <textarea name=”comment” rows=”5″ cols=”40″></textarea>
   <br><br>
   Gender:
   <input type=”radio” name=”gender” value=”female”>Female
   <input type=”radio” name=”gender” value=”male”>Male
   <span class=”error”>* <?php echo $genderError;?></span>
   <br><br>
   <input type=”submit” name=”submit” value=”Submit”> 
</form>

<?php
echo “<h2>Your Input:</h2>”;
echo $name;
echo “<br>”;
echo $email;
echo “<br>”;
echo $website;
echo “<br>”;
echo $comment;
echo “<br>”;
echo $gender;
?>

</body>
</html>

PHP Form Validation

* required field.

Your Input:

Name
Test@gmail.com
www.example.com
Test Comment
Female