/* -------------------------------------------------------------------------- */
		/*  Set up the TF namespace.                                                  */
		/* -------------------------------------------------------------------------- */
		
		var TF = window.TF || {};
			
		/* -------------------------------------------------------------------------- */
		/*  Functions to initialize and perform the scrolling anchor links.           */
		/* -------------------------------------------------------------------------- */
		
		TF.Scroller = function () {
		
			var stepIncrement = 50;	// The number of pixels that each step moves the window.
			var stepDelay = 10;	// The number of milliseconds between steps.
			var limit = 6 * 1000;	// After 6 seconds the scroll is killed.
			
			var running = false;
			
			/* Recursive scrolling method. Steps through the complete scroll. */
				
			function scrollStep(to, dest, down) {
			
				if(!running || (down && to >= dest) || (!down && to <= dest)) {
					TF.Scroller.killScroll();
					return;
				}
		
				if((down && to >= (dest - (2 * stepIncrement))) ||
				   (!down && to <= (dest - (2 * stepIncrement)))) {
					stepIncrement = stepIncrement * .55;
				}
		
				window.scrollTo(0, to);
				
				// Assign the returned function to a public method.
				
				TF.Scroller.nextStep = callNext(+to + stepIncrement, dest, down);
		
				window.setTimeout(TF.Scroller.nextStep, stepDelay);
			}
			
			/* Create a closure so that scrollStep can be accessed by window.setTimeout(). */
			
			function callNext(to, dest, down) {
			
				return function() { scrollStep(to, dest, down); };
			}
		
			return {
			
				nextStep: null,
				killTimeout: null,
			
				/* Sets up and calls scrollStep. */
			
				anchorScroll: function(e, obj) {
		
					var clickedLink = YAHOO.util.Event.getTarget(e);
					var anchorId = clickedLink.href.replace(/^.*#/, '');
					var target = YAHOO.util.Dom.get(anchorId);
					
					if(target) {
					
						YAHOO.util.Event.stopEvent(e);
						running = true;
						
						var yCoord = ((YAHOO.util.Dom.getY(target) - 6) < 0) ? 0 : YAHOO.util.Dom.getY(target) - 6;
						var currentYPosition = (document.all) ? document.body.scrollTop : window.pageYOffset;
						var down = true;
			
						if(currentYPosition > yCoord) {
							stepIncrement *= -1;
							down = false;
						}
			
						// Stop the scroll once the time limit is reached.
			
						TF.Scroller.killTimeout = window.setTimeout(TF.Scroller.killScroll, limit);
			
						scrollStep(currentYPosition + stepIncrement, yCoord, down);	
					}
				},
				
				/* Kill the scroll after a timeout, to prevent an endless loop. */
				
				killScroll: function() {
					window.clearTimeout(TF.Scroller.killTimeout);
					running = false;
					stepIncrement = 50;			
				},
			
				/* Attach the scrolling method to the links with the class 'scrolling-link'. */
		
				init: function() {
				
					var links = YAHOO.util.Dom.getElementsByClassName('scrolling-link', 'a');
					YAHOO.util.Event.addListener(links, 'click', TF.Scroller.anchorScroll, TF.Scroller, true);
				}
			}
		
		} ();
		
		YAHOO.util.Event.onAvailable('doc', TF.Scroller.init, TF.Scroller, true);