Javascript Validation for email (regular expression) English translation

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 the codeThe code is as follows:

 
function validate(form_id,email) { 
var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/; 
var address = [form_id].elements[email].value; 
if((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 the codeThe code is as follows:

 
<form  method="post" action="" onsubmit="javascript:return validate('form_id','email');"> 
<input type="text"  name="email" /> 
<input type="submit" value="Submit" /> 
</form> 

You should not rely purely on client side validation on your website / web application, if the user has javascript disabled this will not work. Always validate on the server.
from:　/blog/javascript-validation/