var el, timer;
function bannerMove(){
   //alert( 'document.body.clientHeight = ' + document.body.clientHeight );
   var isSafari = (navigator.appVersion.indexOf( "Safari" ) > -1);
   var topScroll = document.documentElement ? document.documentElement.scrollTop : document.body.scrollTop;
   var width  = el.offsetWidth; //parseInt(document.defaultView.getComputedStyle(el,null).getPropertyValue('width')),
       height  = el.offsetHeight; //parseInt(document.defaultView.getComputedStyle(el,null).getPropertyValue('height')),
       sw = isSafari ? window.innerWidth : ( document.documentElement ? document.documentElement.clientWidth : document.body.clientWidth ),
       sh = isSafari ? window.innerHeight : ( document.documentElement ? document.documentElement.clientHeight : document.body.clientHeight );
   el.style.left = ( sw - width )/2 + 'px';
   el.style.top  = ( sh - height )/2 + topScroll + 'px';

}


function showBanner(){
   el = document.getElementById('banner');
   if( el ) {
      el.style.visibility='visible';
      bannerMove();
      if( window.addEventListener  ) {
         window.addEventListener('resize', bannerMove, false)
         window.addEventListener('scroll', bannerMove, false)
      } else {
         window.attachEvent( 'onresize', bannerMove );
         window.attachEvent( 'onscroll', bannerMove );
      }
      timeout = parseInt(timeout);
      if( timeout > 0 ) timer = setTimeout( hideBanner, 1000*timeout );
   }
   return true;
}


function hideBanner(){
   clearTimeout(timer);
   if( el ) el.style.display='none';
   if( window.removeEventListener  ) {
      window.removeEventListener('resize', bannerMove, false)
      window.removeEventListener('scroll', bannerMove, false)
   } else {
      window.detachEvent( 'onresize', bannerMove );
      window.detachEvent( 'onscroll', bannerMove );
   }
   return true;
}

if( window.addEventListener  ) {
   window.addEventListener( 'load', showBanner, false );
} else {
   window.attachEvent( 'onload', showBanner );
}

//Event.domReady.add( showBanner );