function check_email(email)
{
	var pattern=/^[a-zA-Z0-9_]+[a-zA-Z0-9\._-]*@[a-zA-Z0-9\.-]+[a-zA-Z0-9]+\.[a-zA-Z]{2,}$/i
    return (pattern.test(email));
}
function check_field(field)
{
    var pattern=/^[a-zA-Z0-9]{2,}$/i
    return (pattern.test(field));
}