function isEmailAddress(string) {
    return /^[^@]+@[^.]+(\.[^.]+)+$/.test(string);
}

function validate(form) {
    var noerror = true;
    var invalidemail = false;
    var ischecked = false;
    var controls = form.elements,
        emailAddress = controls['Email'].value;

   
   	  if(!isEmailAddress(emailAddress))
   	  {
   	   	alert('Please enter a valid email address');
   	   	return false;
   	  }
   	
   
}