/* Smooth scrolling
   Changes links that link to other parts of this page to scroll
   smoothly to those links rather than jump to them directly, which
   can be a little disorienting.
   
   sil, http://www.kryogenix.org/
   
   v1.0 2003-11-11
   v1.1 2005-06-16 wrap it up in an object
*/

var scroll_interval;
var scroll_steps = 50;

function smoothScroll(id) {
	destinationLink = document.getElementById(id);
	
	// Find the destination's position
    var destx = destinationLink.offsetLeft; 
    var desty = destinationLink.offsetTop;
    var thisNode = destinationLink;
    while (thisNode.offsetParent && (thisNode.offsetParent != document.body)) {
      thisNode = thisNode.offsetParent;
      destx += thisNode.offsetLeft;
      desty += thisNode.offsetTop;
    }
  
    // Stop any current scrolling
    clearInterval(scroll_interval);
  
    cypos = getCurrentYPos();
  
    stepsize = parseInt((desty-cypos)/scroll_steps);
    scroll_interval = setInterval('scrollWindow('+stepsize+','+desty+',"'+id+'")',10);

}


function scrollWindow(scramount,dest,anchor) 
{
    wascypos = getCurrentYPos();
    isAbove = (wascypos < dest);
    window.scrollTo(0,wascypos + scramount);
    iscypos = getCurrentYPos();
    isAboveNow = (iscypos < dest);
    if ((isAbove != isAboveNow) || (wascypos == iscypos)) {
      // if we've just scrolled past the destination, or
      // we haven't moved from the last scroll (i.e., we're at the
      // bottom of the page) then scroll exactly to the link
      window.scrollTo(0,dest);
      // cancel the repeating timer
      clearInterval(scroll_interval);
    }
}


function getCurrentYPos() {
    if (document.body && document.body.scrollTop)
      return document.body.scrollTop;
    if (document.documentElement && document.documentElement.scrollTop)
      return document.documentElement.scrollTop;
    if (window.pageYOffset)
      return window.pageYOffset;
    return 0;
  }