browserName=navigator.appName; 
browserVer=parseInt(navigator.appVersion);

if ((browserName=="Netscape" && browserVer >= 3) || (browserName=="Microsoft Internet Explorer" && browserVer >= 4))    
   version="CanRunScript";
else
   version="CannotRunScript";


function on(imgName)
	{
	if (version == "CanRunScript")
		{
		imgOn=eval(imgName + "on.src");
		document[imgName].src= imgOn;
		}
	}

function hover(imgName)
	{
	if(version == "CanRunScript")
		{
		imgHover=eval(imgName + "hover.src");
		document[imgName].src=imgHover;
		}
	}

function off(imgName)
	{
	if (version == "CanRunScript")
		{
		imgOff=eval(imgName + "off.src");
		document[imgName].src= imgOff;
		}
	}