// Validate the email address is the correct format.
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) {
		// if it's invalid do this
	  alert('How am I going to contact you without a valid email address?');
	  $(document.forms[form_id].elements[email]).focus();
	  return false;
   }
}