function SwitchGif(imgDocID,ImgObjName)
{   if (navigator.appName== "Netscape" && parseInt(navigator.appVersion) >= 3)
       document.images[imgDocID].src = eval(ImgObjName + ".src")
    else if (navigator.appName != "Netscape" && parseInt(navigator.appVersion) >= 4) 
       document.images[imgDocID].src = eval(ImgObjName + ".src")
}