Centering Left Aligned Site In Browser?

I'm using a javascript to center my absolutely-positioned left-aligned site. However, it's not perfectly centered in the browser and I'd like to fix it. I set the width to 788px (embedded Div Layout CSS). Here is the link to the site: [URL]

Below is the javascript code:
window.onresize=positionPage;
String.prototype.trim = function() { return this.replace(/^s+|s+$/, ''); };
function positionPage(){
Width = 0;
if(window.innerWidth){
Width = window.innerWidth;
}if(document.body.clientWidth){
Width = document.body.clientWidth;
}Left = Math.floor((Width - 992) / 2);
if(Left > 0){
document.getElementById("Div-Layout").style.left = Left + "px";
}}
<!--
function MM_reloadPage(init) {
//reloads the window if Nav4 resized
if (init==true) with (navigator) {
if ((appName=="Netscape")&&(parseInt(appVersion)==4)) {
document.MM_pgW=innerWidth; document.MM_pgH=innerHeight;
onresize=MM_reloadPage; }}
else if (innerWidth!=document.MM_pgW
|| innerHeight!=document.MM_pgH) location.reload();
}
MM_reloadPage(true);
//-->