title: IE11 in IE7mode not triggering mousewheel event
body: <p>I've not found the IE7 mode version of this specifically addressed. I've tried various versions of this, working fine in Chrome, FF, IE9+, but not in IE11 in forced IE7 mode, a client server-set requirement :-(. </p>
  
  <p>IE7 mode alerts "mousewheel" as the wheelEvent , but never even calls first alert line of scrollHandler() on mouse wheel, so doesn't seem to be attaching the event/handler via window.attachEvent?</p>
  
  <pre><code>        var wheelEvent = "onwheel" in document.createElement("div") ? "wheel" : // Modern browsers support "wheel"
            document.onmousewheel !== undefined ? "mousewheel" : // Webkit and IE support at least "mousewheel"
            "DOMMouseScroll"; // let's assume that remaining browsers are older Firefox
  
      function scrollHandler(wheelEvent) {
          alert("scrollHandler "+wheelEvent);
          //upDown = -1 on scroll-down, = 1 on scroll up
  
              if (wheelEvent.wheelDelta) {//chrome
                  upDown = (wheelEvent.wheelDelta % 120 - 0) == -0 ? wheelEvent.wheelDelta / 120 : wheelEvent.wheelDelta / 12;
              } else {//FF
                  var rawAmmount = wheelEvent.deltaY ? wheelEvent.deltaY : wheelEvent.detail;
                  upDown = -(rawAmmount % 3 ? rawAmmount * 10 : rawAmmount / 3);
              }
              scroller(upDown);       
      }
  
      if (window.addEventListener) {//most browsers
          window.addEventListener(wheelEvent, scrollHandler );
      }else if (window.attachEvent){//IE7...
          alert("IE7 - window.attachEvent: " + wheelEvent);
          window.attachEvent(wheelEvent, scrollHandler);
      }
  </code></pre>