PHP Forms Validate E-mail and URL

📧 PHP Forms – Validate E-mail and URL

Validating email addresses and URLs is essential to ensure users provide properly formatted and safe data. PHP provides built-in functions and filters to handle this efficiently.

1️⃣ HTML Form Example

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>">
E-mail: <input type="text" name="email">
<span style="color:red"><?php echo $emailErr; ?></span><br><br>

Website: <input type="text" name="website">
<span style="color:red"><?php echo $websiteErr; ?></span><br><br>

<input type="submit" name="submit" value="Submit">
</form>

E-mail: <input type="text" name="email">

Website: <input type="text" name="website">

</form>

2️⃣ PHP Script to Validate Email and URL

<?php
$email = $website = "";
$emailErr = $websiteErr = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {

// Email Validation
if (empty($_POST["email"])) {
$emailErr = "Email is required";
} else {
$email = test_input($_POST["email"]);
// Validate email format
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
$emailErr = "Invalid email format";
}
}

// Website Validation (Optional)
if (!empty($_POST["website"])) {
$website = test_input($_POST["website"]);
// Validate URL format
if (!filter_var($website, FILTER_VALIDATE_URL)) {
$websiteErr = "Invalid URL";
}
}
}

// Function to sanitize input
function test_input($data) {
$data = trim($data); // Remove spaces
$data = stripslashes($data); // Remove slashes
$data = htmlspecialchars($data); // Convert special characters
return $data;
}
?>

<?php

$email = $website = "";

$emailErr = $websiteErr = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {

// Email Validation

if (empty($_POST["email"])) {

$emailErr = "Email is required";

} else {

$email = test_input($_POST["email"]);

// Validate email format

if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {

$emailErr = "Invalid email format";

}

// Website Validation (Optional)

if (!empty($_POST["website"])) {

$website = test_input($_POST["website"]);

// Validate URL format

if (!filter_var($website, FILTER_VALIDATE_URL)) {

$websiteErr = "Invalid URL";

}

// Function to sanitize input

function test_input($data) {

$data = trim($data); // Remove spaces

$data = stripslashes($data); // Remove slashes

$data = htmlspecialchars($data); // Convert special characters

return $data;

}

3️⃣ Display Validated Data

4️⃣ Key Points

filter_var() Function:
- FILTER_VALIDATE_EMAIL → Checks valid email format
- FILTER_VALIDATE_URL → Checks valid URL format
Empty vs Optional Fields:
- Email is usually required → use empty()
- Website can be optional → only validate if not empty
Sanitization Before Validation:
Always use trim(), stripslashes(), htmlspecialchars() to clean input.

5️⃣ Example Input & Output

Input Email	Input Website	Output
test@example.com	https://example.com	Valid
invalid-email	example	Invalid email & URL
blank	https://site.com	Email required
user@mail.com		Valid (website optional)

🏁 Summary

Use filter_var() for validating email and URL.
Always sanitize input before validating.
Optional fields should only be validated if filled.
Always combine HTML form validation (optional) with server-side PHP validation.

PHP Forms Validate E-mail and URL