/** Event handler for mouse wheel event.
		 */
		function wheel(event){
				  var delta = 0;
				  if (!event) /* For IE. */
							 event = window.event;
				  if (event.wheelDelta) { /* IE/Opera. */
							 delta = event.wheelDelta/120;
							 /** In Opera 9, delta differs in sign as compared to IE.
							  */
							 if (window.opera)
										delta = -delta;
				  } else if (event.detail) { /** Mozilla case. */
							 /** In Mozilla, sign of delta is different than in IE.
							  * Also, delta is multiple of 3.
							  */
							 delta = -event.detail/3;
				  }
				  /** If delta is nonzero, handle it.
					* Basically, delta is now positive if wheel was scrolled up,
					* and negative, if wheel was scrolled down.
					*/
				  if (delta)
							 handle(delta);
				  /** Prevent default actions caused by mouse wheel.
					* That might be ugly, but we handle scrolls somehow
					* anyway, so don't bother here..
					*/
				  if (event.preventDefault)
							 event.preventDefault();
			event.returnValue = false;
		}
		
		/** Initialization code. 
		 * If you use your own event management code, change it as required.
		 */
		if (window.addEventListener)
				  /** DOMMouseScroll is for mozilla. */
				  window.addEventListener('DOMMouseScroll', wheel, false);
		/** IE/Opera. */
		window.onmousewheel = document.onmousewheel = wheel;