/*
Code written by Scott Andrew
Source: http://www.sitepoint.com/article/scroll-smoothly-javascript/3/
Modified to the requests of main script by Gerhard Baumgartner
*/

function smoothscroll_init()
{
	// 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
     		smoothscroll_addevent(lnk, 'click', smoothscroll_do);
   		}
 	}
}

function smoothscroll_do(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 = smoothscroll_getcurrentypos();
 	
 	ss_stepsize = parseInt((desty - cypos) / ss_STEPS);
 	ss_INTERVAL = setInterval('smoothscroll_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();
 	}
}

function smoothscroll_scrollwindow(scramount,dest,anchor)
{
 	wascypos = smoothscroll_getcurrentypos();
 	isAbove = (wascypos < dest);
 	window.scrollTo(0, wascypos + scramount);
 	iscypos = smoothscroll_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;
 	}
}

function smoothscroll_addevent(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;
 	}
}  

function smoothscroll_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;
}

var ss_INTERVAL;
var ss_STEPS = 25;