/**
 * 
 * credits for this plugin go to brandonaaron.net
 *   
 * unfortunately his site is down
 * 
 * @param {Object} up
 * @param {Object} down
 * @param {Object} preventDefault
 */
jQuery.fn.extend({
  mousewheel: function(up, down, preventDefault) {
    return this.hover(
      function() {
        jQuery.event.mousewheel.giveFocus(this, up, down, preventDefault);
      },
      function() {
        jQuery.event.mousewheel.removeFocus(this);
      }
    );
  },
  mousewheeldown: function(fn, preventDefault) {
    return this.mousewheel(function(){}, fn, preventDefault);
  },
  mousewheelup: function(fn, preventDefault) {
    return this.mousewheel(fn, function(){}, preventDefault);
  },
  unmousewheel: function() {
    return this.each(function() {
      jQuery(this).unmouseover().unmouseout();
      jQuery.event.mousewheel.removeFocus(this);
    });
  },
  unmousewheeldown: jQuery.fn.unmousewheel,
  unmousewheelup: jQuery.fn.unmousewheel
});


jQuery.event.mousewheel = {
  giveFocus: function(el, up, down, preventDefault) {
    if (el._handleMousewheel) jQuery(el).unmousewheel();
    
    if (preventDefault == window.undefined && down && down.constructor != Function) {
      preventDefault = down;
      down = null;
    }
    
    el._handleMousewheel = function(event) {
      if (!event) event = window.event;
      if (preventDefault)
        if (event.preventDefault) event.preventDefault();
        else event.returnValue = false;
      var delta = 0;
      if (event.wheelDelta) {
        delta = event.wheelDelta/120;
        if (window.opera) delta = -delta;
      } else if (event.detail) {
        delta = -event.detail/3;
      }
      if (up && (delta > 0 || !down))
        up.apply(el, [event, delta]);
      else if (down && delta < 0)
        down.apply(el, [event, delta]);
    };
    
    if (window.addEventListener)
      window.addEventListener('DOMMouseScroll', el._handleMousewheel, false);
    window.onmousewheel = document.onmousewheel = el._handleMousewheel;
  },
  
  removeFocus: function(el) {
    if (!el._handleMousewheel) return;
    
    if (window.removeEventListener)
      window.removeEventListener('DOMMouseScroll', el._handleMousewheel, false);
    window.onmousewheel = document.onmousewheel = null;
    el._handleMousewheel = null;
  }
};