window.onload = function(){
var links = document.getElementsByTagName("a");
for (var i=0; i<links.length; i++){
if (links[i].className=="popUp"){
links[i].setAttribute("title","click to open in a pop up window") 
links[i].onclick = function(){
popUp(this.getAttribute("href"));
return false;
}
}
}
}

function popUp(file) {
newWin = window.open (file, "", "width=500, height=480");
}