function check()
{
	if (document.login.username.value=="")
	{
		alert("Username cannot be null");
		document.login.username.focus();
		return false;
	}
	if (document.login.password.value == "")
	{
		alert("Password cannot be null");
		document.login.password.focus();
		return false;
	}
	return true;
}