PHP Form Validation With Regular Expressions Example

PHP

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Jun 18, 2021

Hi guys,

Today i will explained how to use php form validation with Regular Expressions in your form. This example is so easy to use in php. This example to i am a create a bootstrap form and set to the required validation & Regular Expressions validation in your form input.

This example to i am create a name,email,website,comment,and gender field and set to the required validation & Regular Expressions validation in php.

So let's start to the example.

Example :

index.php

<?php
    $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"])) {
            $websiteErr = "website is required";
        } else {
            $website = test_input($_POST["website"]);
            // check if URL address syntax is valid
            if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {
                $websiteErr = "Invalid URL";
            }    
        }
        if (empty($_POST["comment"])) {
            $commentErr = "Comment is required";
        } else {
            $comment = test_input($_POST["comment"]);
        }
        if (empty($_POST["gender"])) {
            $genderErr = "Gender is required";
        } else {
            $gender = test_input($_POST["gender"]);
        }
    }
    function test_input($data) {
        $data = trim($data);
        $data = stripslashes($data);
        $data = htmlspecialchars($data);
        return $data;
    }
?>
<!DOCTYPE html>
<html lang="en">
<head>
    <title>PHP Form Validation With Regular Expressions Example</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css">
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script>
    <style>
        .error {
            color: #FF0000;
        }
    </style>
</head>
<body>
    <div class="container">
      <h2>PHP Form Validation With Regular Expressions Example</h2>
      <p><span class="error">* All Fields required</span></p>
        <form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
            <div class="form-group">
                <label for="name">Name:<span class="error">*</span></label>
                <input type="text" class="form-control" id="name" placeholder="Enter Name" name="name">
                <span class="error"><?php echo $nameErr;?></span>
            </div>
            <div class="form-group">
                <label for="email">Email:<span class="error">*</span></label>
                <input type="email" class="form-control" id="email" placeholder="Enter email" name="email">
                <span class="error"><?php echo $emailErr;?></span>
            </div>
            <div class="form-group">
                <label for="website">Website:</label> 
                <input type="website" class="form-control" id="website" placeholder="Enter Website" name="website">
                <span class="error"><?php echo $websiteErr;?></span>
            </div>
            <div class="form-group">
                <label>Comment:</label>
                <textarea name="comment" class="form-control" rows="5" cols="40"></textarea>
                <span class="error"><?php echo $commentErr;?></span>
            </div>
            <label>Gender:<span class="error">*</span></label><br>
            <label class="radio-inline">
                <input type="radio" name="gender" value="male"> Male
            </label>
            <label class="radio-inline">
                <input type="radio" name="gender" value="female"> Female
            </label>
            <label class="radio-inline">
                <input type="radio" name="gender" value="other"> Other
            </label><br>
            <span class="error"><?php echo $genderErr;?></span>
            <br>
            <button type="submit" class="btn btn-primary">Submit</button>
        </form>
    </div>
    <div class="container mt-3 mb-3">
        <div class="row">
            <div class="col-md-12">
                <?php
                    echo "<h2>Your Output:</h2>";
                    echo $name;
                    echo "<br>";
                    echo $email;
                    echo "<br>";
                    echo $website;
                    echo "<br>";
                    echo $comment;
                    echo "<br>";
                    echo $gender;
                ?>
            </div>
        </div>
    </div>
</body>
</html>

Output

Your Output:
Evelyn Mason
[email protected]
https://tryphp.w3schools.com/
how are you.
male

now you can check your own.