function PageScroll() {
   var yscr;

   if (self.pageYOffset) {
      yscr = self.pageYOffset;
   }
   else if (document.documentElement && document.documentElement.scrollTop) {
      yscr = document.documentElement.scrollTop;
   }
   else if (document.body) {
      yscr = document.body.scrollTop;
   }

   return yscr;
}

function GetCenter() {
   var availHeight;
   var availWidth;

   if (typeof (window.innerWidth) == 'number') {
      availHeight = window.innerHeight;
      availWidth = window.innerWidth;
   }
   else if (document.documentElement && (document.documentElement.clientWidth || document.documentElement.clientHeight)) {
      availHeight = document.documentElement.clientHeight;
      availWidth = document.documentElement.clientWidth;
   }
   else if (document.body && (document.body.clientWidth || document.body.clientHeight)) {
      availHeight = document.body.clientHeight;
      availWidth = document.body.clientWidth;
   }

   var center = new Array(availHeight, availWidth);
   return center;
}

function WheelHandler(event) {
   var delta = 0;
   if (!event)
      event = window.event;

   if (event.wheelDelta) {
      delta = event.wheelDelta / 120;
      if (window.opera)
         delta = -delta;
   }
   else if (event.detail) {
      delta = -event.detail / 3;
   }

   if (delta) {
      if ($get('UpdateProgress1').style.display != "none") {
         CancelVoid(event);
      }
   }
}

if (window.addEventListener) {
   window.addEventListener('DOMMouseScroll', WheelHandler, false);
}

window.onmousewheel = document.onmousewheel = WheelHandler;