var submitcount=0;
function checkLogin(form)
{	
	if ((form.D1.value)==(""))
	{
		alert("Please enter your order entry ID");
		return false;
	}
	else{okay = true;}
	if ((form.D2.value)==(""))
	{
		alert("Please enter your password");
		return false;
	}
	else{okay = true;}

        if (submitcount==0)
        {
		submitcount++;
                return true;
	}
        else
        {
		alert("This form has already been submitted. Thanks!");
		return false;
	}     
}