IMAGE01 = "images/on.gif"  
IMAGE02 = "images/off.gif"

function imgover(imgname){
     imgname.src = IMAGE01
}

function imgout(imgname){
     imgname.src = IMAGE02
}

function formHandler(form) {
var windowprops = "height=550,width=430,location=no, left=497, top=55,"
+ "scrollbars=yes,menubars=no,toolbars=no,resizable=no;"

var URL = form.site.options[form.site.selectedIndex].value;
popup = window.open(URL,"MenuPopup",windowprops);
}