function f1()
{

  if(fd.regno.value=="")
  { alert("Enter Registration number");fd.regno.focus(); return false; }
  if(fd.regno.value!="")
    	{
    	
    	// only allow numbers to be entered
    	var checkOK = "0123456789";
    	var checkStr = fd.regno.value;
    	var allValid = true;
    	var allNum = "";
    	if (checkStr.length==6 && checkStr!="0000000")
    	{
    	for (i = 0;  i < checkStr.length;  i++)
    	{
    		ch = checkStr.charAt(i);
    		for (j = 0;  j < checkOK.length;  j++)
    		if (ch == checkOK.charAt(j))
    		break;
    		if (j == checkOK.length)
    		{allValid = false;break;}
    		if (ch != ",")
    		allNum += ch;
    	}
    	}
    	else {alert("Enter Valid Registration Number.");fd.regno.focus();fd.regno.select(); return false;}
    	if (!allValid)
    	{alert("Enter Valid Registration Number.");fd.regno.focus();fd.regno.select();  return false; }
	}
  if(fd.dd_no.value=="")
  { alert("Enter DD number");fd.dd_no.focus(); return false; }
  if(fd.dd_no.value!="")
  	{
  	
  	// only allow numbers to be entered
  	var checkOK = "0123456789";
  	var checkStr = fd.dd_no.value;
  	var allValid = true;
  	var allNum = "";
  	if (checkStr.length==6 && checkStr!="000000")
  	{
  	for (i = 0;  i < checkStr.length;  i++)
  	{
  		ch = checkStr.charAt(i);
  		for (j = 0;  j < checkOK.length;  j++)
  		if (ch == checkOK.charAt(j))
  		break;
  		if (j == checkOK.length)
  		{allValid = false;break;}
  		if (ch != ",")
  		allNum += ch;
  	}
  	}
  	else {alert("Enter Valid DD Number.");fd.dd_no.focus();fd.dd_no.select(); return false;}
  	if (!allValid)
  	{alert("Enter Valid DD Number.");fd.dd_no.focus(); fd.dd_no.select(); return false; }
	}
   return true;     	           			                          
}