var sName = navigator.appName;
var iVer = parseInt(navigator.appVersion);
var benable;
if (sName == "Netscape" && iVer >= 4) 
{
benable = 1;
} 
else if (sName == "Microsoft Internet Explorer" && iVer >= 4) 
{
benable = 1;
} 
else 
{
benable = 0;
}
if (benable == 1) 
{
document.write('<img src="images/screenres.gif?' +
'width=' + screen.width + '&' +
'height=' + screen.height + '&' +
'depth=' + screen.colorDepth + '">'); 
}