How to Validate Email in JavaScript with Regular Expression

We have seen many Regular Expression tutorials in VB.NET and C-sharp, this is our first JavaScript tutorial on Regular Expressions. So today we’ll see how to validate an email address that's being entered to a textbox. We have a textbox and a button, when you enter something into the textbox and click on the “validate”  button it’ll tell if It’s an email address or not(being noob GRRR!).

Add our JavaScript first(make sure you add it to the head) :
<script type="text/javascript"> function inputemailcheck(emailaddress){ //Down below we have the Regular Expressions into a Variable var regex = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/; //Now this where the email is being checked with an if condition if(regex.test(emailaddress)){ return "That is indeed a Email Address"; }else{ return "It is not a Email Address"; } } </script>
Next add the input box and the validate button :
<input type="text" id="emailaddress"> <button onclick="alert(inputemailcheck(document.getElementById('emailaddress').value))">Validate</button>

That’s all. You can use this for some kind of subscription button or register/login forms. I hope this little snippet is helpful for you.