var ld=(document.all);

var ns4=document.layers;
var ns6=document.getElementById&&!document.all;
var ie4=document.all;

if (ns4)
ld=document.loading;
else if (ns6)
ld=document.getElementById("loading").style;
else if (ie4)
ld=document.all.loading.style;

function start_loading() {
  if(ns4) {
    ld.visibility="hidden";
  } else if (ns6||ie4) ld.display="none";
}