window.onscroll = crawl_sidebar;
  window.onresize = crawl_sidebar;

  /* Following code has been modified from
     http://www.howtocreate.co.uk/tutorials/javascript/browserwindow
  */
  function getScrollY() {
    var scrOfY = 0;
    if( typeof( window.pageYOffset ) == 'number' ) {
      //Netscape compliant
      scrOfY = window.pageYOffset;
    }
    else if( document.body && document.body.scrollTop ) {
      //DOM compliant
      scrOfY = document.body.scrollTop;
    }
    else if( document.documentElement && document.documentElement.scrollTop ) {
    //IE6 standards compliant mode
      scrOfY = document.documentElement.scrollTop;
    }
    return scrOfY;
  }

  function getViewportHeight() {
    var myHeight = 0;
    if( typeof( window.innerWidth ) == 'number' ) {
      //Non-IE
      myHeight = window.innerHeight;
    } else if( document.documentElement && document.documentElement.clientHeight ) {
      //IE 6+ in 'standards compliant mode'
      myHeight = document.documentElement.clientHeight;
    } else if( document.body && document.body.clientHeight ) {
      //IE 4 compatible
      myHeight = document.body.clientHeight;
    }
    return myHeight;
  }
  /* Above code has been modified from
     http://www.howtocreate.co.uk/tutorials/javascript/browserwindow
  */

/* http://www.quirksmode.org/js/findpos.html */
function findPos(obj) {
	var curleft = curtop = 0;
	if (obj.offsetParent) {
		do {
			curleft += obj.offsetLeft;
			curtop += obj.offsetTop;
		} while (obj = obj.offsetParent);
	} else {
		curleft = obj.offsetLeft;
		curtop = obj.offsetTop;
	}
	return [curleft,curtop];
}

  function crawl_sidebar() {//alert(document.body.style.zoom);return;
    // Get all the relevant elements
    sidebar = document.getElementById(sCrawledDiv);
    contentdiv = document.getElementById(sContainerDiv);

    // Get sidebar and viewport offsets
    sidebar_top = findPos(sidebar)[1];//sidebar.offsetTop;
    sidebar_bottom = sidebar_top + sidebar.offsetHeight;

    viewport_top = getScrollY();
    viewport_bottom = viewport_top + getViewportHeight();

    if ( sidebar_top > viewport_bottom ) {
      // below viewport, move up!
      if ( sidebar.offsetHeight < viewport_bottom - viewport_top ) {
        // align top when sidebar is shorter than viewport height;
        crawl = viewport_top - sidebar_top + 17;
      }
      else {
        // otherwise, align bottom
        crawl = viewport_bottom - sidebar_bottom - 17;
      }
    }
    else if ( sidebar_bottom < viewport_top ) {
      // above viewport, move down!
        crawl = viewport_top - sidebar_top + 17;
    }
    else {
      // within viewport, do nothing.
      return;
    }

    if ( typeof sidebar.style.marginTop == "undefined" ) {
      sidebar_marginTop = 0;
    }
    else {
      sidebar_marginTop = sidebar.style.marginTop.replace(/px/,'') - 0;
    }

    sidebar_marginTop += crawl;

    if ( sidebar_marginTop < 0 ) {
      sidebar_marginTop = 0;
    }
    else if ( sidebar_marginTop + sidebar.offsetHeight > contentdiv.offsetHeight ) {
      // try to avoid pushing down the footer
      sidebar_marginTop = contentdiv.offsetHeight - sidebar.offsetHeight;
    }

    sidebar.style.marginTop = sidebar_marginTop + "px";

  }