/* 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 ss = {fixAllLinks:function () {
	// Get a list of all links in the page
	var allLinks = document.getElementsByTagName('a');
	// Walk through the list
	for (var i = 0; i < allLinks.length; i++) {
		var lnk = allLinks[i];
		if ((lnk.href && lnk.href.indexOf('#') != -1) && ((lnk.pathname == location.pathname) || ('/' + lnk.pathname == location.pathname)) && (lnk.search == location.search)) {
			// If the link is internal to the page (begins in #)
			// then attach the smoothScroll function as an onclick
			// event handler
			ss.addEvent(lnk, 'click', ss.smoothScroll);
		}
	}
}, smoothScroll:function (e) {
	// This is an event handler; get the clicked on element,
	// in a cross-browser fashion
	if (window.event) {
		target = window.event.srcElement;
	} else if (e) {
		target = e.target;
	} else {
		return;
	}
	// Make sure that the target is an element, not a text node
	// within an element
	if (target.nodeType == 3) {
		target = target.parentNode;
	}
	// Paranoia; check this is an A tag 
	if (target.nodeName.toLowerCase() != 'a') {
		return;
	}
	// Find the <a name> tag corresponding to this href 
	// First strip off the hash (first character)
	anchor = target.hash.substr(1);
	// 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);
	// And stop the actual click happening
	if (window.event) {
		window.event.cancelBubble = true;
		window.event.returnValue = false;
	}
	if (e && e.preventDefault && e.stopPropagation) {
		e.preventDefault();
		e.stopPropagation();
	}
}, 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;
}, addEvent:function (elm, evType, fn, useCapture) {
	// addEvent and removeEvent
	// cross-browser event handling for IE5+,  NS6 and Mozilla
	// By Scott Andrew
	if (elm.addEventListener) {
		elm.addEventListener(evType, fn, useCapture);
		return true;
	} else if (elm.attachEvent) {
		var r = elm.attachEvent("on" + evType, fn);
		return r;
	} else {
		alert("Handler could not be removed");
	}
}};
ss.STEPS = 25;
ss.addEvent(window, "load", ss.fixAllLinks);