function checkform()
{
	var x = document.forms[0].email.value;
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if(!filter.test(x))
	{
		alert('Invalid email address!');
		return false;
	}
	document.forms[0].submit();
	return true;
}