function Is() {
var agent = navigator.userAgent.toLowerCase();
this.major = parseInt(navigator.appVersion);
this.minor = parseFloat(navigator.appVersion);
this.ns = ((agent.indexOf('mozilla') != -1) &&
(agent.indexOf('spoofer') == -1) && (agent.indexOf('compatible') == -1) && (agent.indexOf('opera') == -1) && (agent.indexOf('webtv') == -1));
this.ns2 = (this.ns && (this.major == 2));
this.ns3 = (this.ns && (this.major == 3));
this.ns4 = (this.ns && (this.major == 4));
this.ns6 = (this.ns && (this.major >= 5));
this.ie = (agent.indexOf("msie") != -1);
this.ie3 = (this.ie && (this.major < 4));
this.ie4 = (this.ie && (this.major == 4) &&
(agent.indexOf("msie 5.0")   == -1));
this.ie5 = (this.ie && (this.major == 4) &&
(agent.indexOf("msie 5.0") != -1));
this.ieX = (this.ie && !this.ie3 && !this.ie4);
}
var is = new Is();
function layerObject(id,left,top,visibility) {
if (is.ie5||is.ns6){
this.obj = document.getElementById(id).style;
this.obj.left = left;
this.obj.top = top;
this.obj.visibility = visibility;
return this.obj;
}
else if(is.ie4) {
this.obj = document.all[id].style;
this.obj.left = left;
this.obj.top = top;
this.obj.visibility = visibility;
return this.obj;
}
else if(is.ns4) {
this.obj = document.layers[id];
this.obj.left = left;
this.obj.top = top;
this.obj.visibility = visibility;
return this.obj;
   }
}
function layerSetup() {
backgroundLyr = new layerObject('backgroundLayer', 0,0,'visible');
}
function findSize() {
if(is.ns4 ||is.ns6) {
available_width=innerWidth;
available_height=innerHeight;
layerSetup();
} else if(is.ie4 || is.ie5) {
available_width=document.body.clientWidth;
available_height=document.body.clientHeight;
layerSetup();
   }
}
function winResize() {
if(is.ns4 ||is.ns6||is.ie4||is.ie5) {
history.go(0);
   }
}



<!-- Begin images -->
function Help(width_size, height_size, daLink) {
    var helpWnd=window.open(daLink,"help",'left=100,top=100,height='+height_size+',width='+width_size+',resizable=yes,scrollbars=yes,status=no,toolbar=no,menubar=no,location=no');
}
<!-- End -->