function Is() {
    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)));
    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.ie55  = (this.ie && (this.major      ==    4) && 
                 (agent.indexOf("msie 5.5")   !=   -1));
    this.ie6   = (this.ie && (agent.indexOf("msie 6.0")!=-1) );
}

var is = new Is();

function layerObject(id,position,left,top,visibility) {
if (is.ie5|| is.ie55||is.ie6|| 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;
}
}
function layerSetup() {
centerLyr = new layerObject('centerLayer','absolute', 
                            page_width/2-25,
                        /*  page_height/2-12,   */
                            'visible');
}