Cable Forum - A little help with my website

Centering layers is a b*stard.

This works however:
Code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">

<html>

<head>

<script>

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/2-100,page_height/2-12,'visible');

}

</script>

<style type="text/css">

<!--

.main { 

font-family: Georgia, "Times New Roman", Times, serif; 

font-size: 16px; 

color: #FBEED5; 

text-decoration: none

}

body {

        margin-left: 0px;

        margin-top: 0px;

        margin-right: 0px;

        margin-bottom: 0px;

        background-color: #FFFFFF;

}

-->

</style> 

<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"></head>

<body onLoad="

if(is.ns6) {

page_width=innerWidth;

page_height=innerHeight;

layerSetup();

} else if(is.ie5 || is.ie55 ||is.ie6) {

page_width=document.body.clientWidth;

page_height=document.body.clientHeight;

layerSetup();

}"

onResize=" history.go(0); ">

<div id="centerLayer" style="position: absolute; width:200px; height:24px; left: 0px; top: 0px; z-index: 6; visibility: hidden;"> 

  <div align="center">centered layer

  </div>

</div>

</body>

</html>
Note, it won't show up centered in Dreamweaver but will in a browser.