/* Modified Smooth scrolling
   Todd Anglin  14 October 2006
   
   Modified:
   Removed functions that attached smooth scroll to all hash 
   links on the page. Exposed smoothScroll function with new 
   parameter that allows you to pass the name of the tag to 
   scroll to.
   
   Original:
   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 ss = {
  smoothScroll: function(anchor) {
    // Now loop all A tags until we find one with that name
    var allLinks = document.getElementsByTagName('a');
    var destinationLink = null;
    for (var i=0;i<allLinks.length;i++) {
      var lnk = allLinks[i];
      if (lnk.name && (lnk.name == anchor)) {
        destinationLink = lnk;
        break;
      }
    }

    // If we didn't find a destination, give up and let the browser do
    // its thing
    if (!destinationLink) return true;

    // 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(ss.INTERVAL);

    cypos = ss.getCurrentYPos();

    ss_stepsize = parseInt((desty-cypos)/ss.STEPS);
    ss.INTERVAL = setInterval('ss.scrollWindow('+ss_stepsize+','+desty+',"'+anchor+'")',10);
  },

  scrollWindow: function(scramount,dest,anchor) {
    wascypos = ss.getCurrentYPos();
    isAbove = (wascypos < dest);
    window.scrollTo(0,wascypos + scramount);
    iscypos = ss.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(ss.INTERVAL);
      // and jump to the link directly so the URL's right
      location.hash = anchor;
    }
  },

  getCurrentYPos: function() {
    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;
  }
}

ss.STEPS = 25;