browser_name = navigator.appName;
browser_version = parseFloat(navigator.appVersion);

if (browser_name == "Netscape" && browser_version >= 3.0) { roll = 'true'; }
else if (browser_name == "Microsoft Internet Explorer" && browser_version >= 4.0) { roll = 'true'; }
else { roll = 'false'; }

// Preload images, if browser supports mouseovers
if (roll == 'true') {

var imglist = new Array (
"images/menu_01b.gif",
"images/menu_02b.gif",
"images/menu_03b.gif",
"images/menu_04b.gif",
"images/menu_05b.gif"

);

var imgs = new Array();

var count;
if (document.images)
for (count=0; count<imglist.length; count++)
{imgs[count]=new Image(); imgs[count].src=imglist[count];}
}