Please help me in my code..

[jjqbunty]

<script type="text/javascript">
            function qtycheck() {
              var l = "qty_'+row_id+'".val;
              var h = "qtyact_value_'+row_id+'".val;
              //alert("hi " + h + " lo " + l);
              if (l > h) {
                qty_1.value=0  
                alert("not allowed");
              } else {
                alert("ok, i'll allow it");
              }
            }
        </script> 

[JMRKER]

Following is based on several assumptions.

 - where is row_id coming from and to what does it refer?

 - you have elements id as qty_???.val and qtyact_value_???.val defined?

 - is qty_1.value defined somewhere or does it represent one of the above?
if you have a numeric ID for an element (ie, row.id) it may not work in all browsers

 - there is more code available?  If yes, show pertinent parts.

Difficult to answer questions fully when there is not enough information provided.  Good Luck!