$(function(){
            $(window).resize(function(){  
         $("#listId").setGridWidth($(window).width());
        });
       });

window.onresize = function  _doResize() {
 var ss = pageSize();
 $("#listId").jqGrid('setGridWidth', ss.WinW-10).jqGrid('setGridHeight', ss.WinH-200);
   }

 function pageSize() {
   var winW, winH;
  if(window.innerHeight) {// all except IE
   winW = window.innerWidth;
   winH = window.innerHeight;
  } else if (document.documentElement && document.documentElement.clientHeight) {// IE 6 Strict Mode
   winW = document.documentElement.clientWidth;
   winH = document.documentElement.clientHeight;
  } else if (document.body) { // other
   winW = document.body.clientWidth;
   winH = document.body.clientHeight;
  }  // for small pages with total size less then the viewport
  return {WinW:winW, WinH:winH};
}