Javascript Validation for email (regular expression) English translation _ Regular expressions

Try testing the following form with valid and invalid email addresses. The
Code uses JavaScript to match the users input with a regular expression.
Function code:

Copy Code code as follows:

function Validate (Form_id,email) {
var reg =/^ ([a-za-z0-9_\-\.]) +\@ ([a-za-z0-9_\-\.]) +\. ([a-za-z]{2,4}) $/;
var address = Document.forms[form_id].elements[email].value;
if (reg.test (address) = = False) {
Alert (' Invalid Email address ');
return false;
}
}

In the forms ' onsubmit ' code call Javascript:return Validate (' form_id ', ' email_field_id ')
How to use:

Copy Code code as follows:

<form id= "form_id" method= "post" action= "action.php" onsubmit= "Javascript:return Validate" (' form_id ', ' email '); " >
<input type= "text" id= "email" name= "email"/>
<input type= "Submit" value= "Submit"/>
</form>

Should not rely purely on client side validation on your website/web, if the user application JavaScript has D this is not work. Always validate on the server.
from:http://www.white-hat-web-design.co.uk/blog/javascript-validation/