JavaScript: Validate email address

Sometime we need to validate email address entered by user on client side, Here i have written a very simple but useful javascript regex to validate email address.

function validate(email) {
 var reg = /^([A-Za-z0-9_\-\.]{2,})+\@([A-Za-z0-9_\-\.]{2,})+\.([A-Za-z]{2,4})$/;
 if(reg.test(email) == false) return true; else return false;
}