// This script originally found at Brand Spanking New:
// http://www.brandspankingnew.net/archive/2005/09/animated_anchor.html
// Then modified for IE support by Steve Cochrane (hq at stevecochrane dot com)

// This is version 2, which is to be used for inline links that point to 
// divs with id attributes, and not empty anchors with name attributes. 
// If you would like to use named anchors please use the first version at:
// http://stevecochrane.com/js/smooth_anchors.js

// initializes the script
addLoadEvent(replaceAnchorLinks);

var scrollInt;
var scrTime, scrSt, scrDist, scrDur, scrInt;


function addLoadEvent(func) {
	var oldonload = window.onload;
	if (typeof window.onload != 'function') {
		window.onload = func;
	}
	else {
		window.onload = function() {
			oldonload();
			func();
		}
	}
}

// Found this script at http://blog.firetree.net/2005/07/04/javascript-find-position/
// Just used here to provide offsetTop functionality for IE
function findPosY(obj) {
	var curtop = 0;

	if (obj.offsetParent) {
		while (1) {
			curtop += obj.offsetTop;
			if (!obj.offsetParent) {
				break;
			}
			obj = obj.offsetParent;
		}
	} else if (obj.y) {
		curtop += obj.y;
	}
	return curtop;
}

function replaceAnchorLinks() {
	var anchors, i, targ, targarr;

	if (!document.getElementById) {
		return;
	}

	// get all anchors
	anchors = document.getElementsByTagName("a");

	for (i=0; i<anchors.length; i++) {
		// check if href links to an id on this page
		if (anchors[i].href.indexOf("#") != -1 && anchors[i].href.indexOf("login=") == -1) {
			// get id of target
			targ = anchors[i].href.substring(anchors[i].href.indexOf("#")+1);

			// find target
			if (document.getElementById(targ)) {
				targarr = document.getElementById(targ);
			}

			if (targarr.getAttribute("id")) {
				anchors[i].className = (targarr.offsetTop < anchors[i].offsetTop) ? "up" : "down";
				anchors[i].id = "__" + targ;	// save target as id with prefix (used in onclick function below)
				anchors[i].onclick = function() {
					try {
						scrollToAnchor(this.id.substring(2));
					}
					catch (e) {}
					return false;
				};
			}
		}
	}
}


/*
SCROLL FUNCTIONS
*/




function scrollPage() {
	scrTime += scrInt;
	if (scrTime < scrDur) {
		window.scrollTo(0, easeInOut(scrTime,scrSt,scrDist,scrDur));
	} else {
		window.scrollTo(0, scrSt+scrDist);
		clearInterval(scrollInt);
	}
}

function scrollToAnchor(aname) {
	var divs, i, ele, elePosY, heightCorrection;

	if (!document.getElementById) {
		return;
	}
	
	// get divs
	divs = document.getElementsByTagName("div");
	for (i=0; i<divs.length; i++) {
		if (divs[i].getAttribute("id") == aname) {
			ele = divs[i];
			i = divs.length;
		}
	}
	
	// Find anchor's Y position
	elePosY = findPosY(ele);
	
	//	The following is just to give some vertical space above where the anchor lands, 
	//	in case you think it stops too close to the top of the window.  Set to 0 if unnecessary.
	heightCorrection = 0;
	
	// set scroll target
	if (typeof (window.pageYOffset) == 'number') {
		// Non-IE modern browsers
		scrSt = window.pageYOffset;
		scrDist = elePosY - heightCorrection - scrSt;
		scrDur = 500;
	} else if (document.documentElement) {
		// IE in Standards Compliance mode
		scrSt = document.documentElement.scrollTop;
		scrDist = elePosY - scrSt;
		if (window.XMLHttpRequest) {
			// IE7
			scrDur = 500;
		} else {
			// IE6
			scrDur = 1500;
		}
	} else if (document.body && (document.body.scrollLeft || document.body.scrollTop)) {
		// DOM compliant method, IE Quirks Mode
		scrSt = document.body.scrollTop;
		scrDist = elePosY - scrSt;
		scrDur = 500;
	}

	scrTime = 0;
	scrInt = 5;
	
	// set interval
	clearInterval(scrollInt);
	scrollInt = setInterval( scrollPage, scrInt );
}




/*
EASING FUNCTIONS
*/

function easeInOut(t,b,c,d) {
	return c/2 * (1 - Math.cos(Math.PI*t/d)) + b;
}