window.onload = function() {
       // check to see that the browser supports the getElementsByTagName method
       // if not, exit the loop
       if (!document.getElementsByTagName) {
          return false;
       }
       // create an array of objects of each link in the document
       var popuplinks = document.getElementsByTagName("a");
       // loop through each of these links (anchor tags)    
       for (var i=0; i < popuplinks.length; i++) {   
          // if the link has a class of "popup"...   
          if (popuplinks[i].getAttribute("class") == "popup") {   
             // add an onclick event on the fly to pass the href attribute   
             // of the link to our second function, openPopUp    
             popuplinks[i].onclick = function() {   
             return openPopUp(this.getAttribute("href"));   
             }    
          }
       }
    }

    function openPopUp(linkURL) {
       var new_window=window.open(linkURL,'popup','width=780,height=650');
       if(!new_window){
	     	return true;
		}
		else {
			return false;
		}
    }