function validate(frm) 
{	
        if (frm.username.value =="")
  			{
				alert("Xin vui long nhap vao ten tai khoan");
				frm.username.focus();
				return (false);
  			}

		if (frm.password.value == "")
  			{
				alert("Xin vui long nhap vao mật khẩu");
				frm.password.focus();
				return (false);
  			}  
  			
/////Kiem tra ok
			
		  	  
  	return (true);
}