Issue 1112 - Properly use polyfills in firstrun and settings pages

html/static/js/settings.js

 "use strict";
 
-function addListener(element, eventType, callback, propagate)
-{
-  if (element.addEventListener)
-  {
-    element.addEventListener(eventType, callback, propagate);
-  }
-  else
-  {
-    element.attachEvent("on" + eventType, callback);
-  }
-}
-
 (function()
 {
   function init()
   {
     var manageButton = document.getElementById("manageExceptions");
-    addListener(manageButton, "click", toggleManage, false);
+    manageButton.addEventListener("click", toggleManage, false);
   }
   
   function toggleManage(ev)
   {
     var exceptions = document.getElementById("exceptions");
     
     if (exceptions.getAttribute("class"))
       exceptions.removeAttribute("class");
     else
       exceptions.setAttribute("class", "visible");
     
     // IE6-only
     if (exceptions.getAttribute("className"))
       exceptions.removeAttribute("className");
     else
       exceptions.setAttribute("className", "visible");
   }
   
   init();
 })();