JavaScript Email Validation Using Regular Expression

It is the simple code to help you create a form with email validation using a regular expression. The function checks the email field against a regex pattern and shows an alert if the format is invalid.

Complete Example

<html>
<head>
<title>JavaScript Email Validation Using Regular Expression</title>
<script type="text/javascript">
    function Validate(input) {
        var format = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;

        if (document.getElementById("email").value.match(format)) {
            document.myform.email.focus();
            return true;
        } else {
            alert("You have entered a wrong email address!");
            document.myform.email.focus();
            return false;
        }
    }
</script>
</head>
<body>
    <h2>Input an email and Submit</h2>
    <form name="myform" action="#">
        <input type="text" name="email" id="email" />
        <input type="submit" name="submit" value="Submit"
               onclick="Validate(document.myform.email)" />
    </form>
</body>
</html>

How the Regex Works

The regular expression pattern /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/ checks that:

The local part (before @) contains word characters, dots, or hyphens.
There is exactly one @ symbol.
The domain contains word characters, dots, or hyphens.
The TLD (e.g. .com, .net) is 2–3 characters long.

Hope this tutorial is useful for you. Keep following PHP Tutorial for Beginners for more help.

JavaScript Email Validation Using Regular Expression | PHP Tutorials for Beginners

Complete Example

How the Regex Works