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));
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,position,left,top,visibility) {
if (is.ie5||is.ns6){
this.obj = document.getElementById(id).style;
this.obj.position = position;
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.position = position;
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.position = position;
this.obj.left = left;
this.obj.top = top;
this.obj.visibility = visibility;
return this.obj;
} 
}


function layerSetup() {

centerLyr = new layerObject('centerLayer','absolute', available_width/2-325,available_height/2-240,'visible');
}