/*******************************************************************************
Gentle Anchors v1.2.1
********************************************************************************
* Author: Kendall Conrad of Angelwatt.com
* Home Page: http://www.angelwatt.com/coding/gentle_anchors.php
* Created: 2008-06-25
* Updated: 2010-12-04
* Description: Gentle Anchors is a page scrolling script for anchor and area tags on a page.
* License:
This work is licensed under a Creative Commons Attribution-Share Alike
3.0 United States License 
http://creativecommons.org/licenses/by-sa/3.0/us/
*******************************************************************************/
Gentle_Anchors = function () {
    //#### Script preferences ####
    // Recommended Speed Range: 4 to 40 (fast to slow) default value 12
    var scrollSpeed = 12;     // Controls speed of scroll:
    var shine = false;   // Whether to use shine effect
    var shineColor = '#dd9'; // Background color for shine
    var shineOutline = '#5f5'; // Outline color for shine; transparent for off
    //#### End script preferences ####
    var timer;      // Timer item
    var elt = null; // the current clicked on element

    // Initialization, grabbing all anchors and adding onclick event
    Init = function () {
        var a = document.getElementsByTagName('a'); // got catch'em all!
        var area = document.getElementsByTagName('area');
        var links = new Array();
        // combine NodeLists together
        for (var x = 0, y = a.length; x < y; links.push(a[x]), x++);
        for (var x = 0, y = area.length; x < y; links.push(area[x]), x++);
        for (var x = 0, l = links.length; x < l; x++) {
            if (links[x].href.match(/#[a-zA-Z0-9:\._-]+/)) {
                links[x].onclick = function (e) {
                    Setup(this.href);
                    return false;
                };
            }
        }
    };
    // Set things up for the scrolling effect
    Setup = function (href) {
        var doc = document;
        if (!href.match(/#([^\?]+)/)) {
            return;
        }
        var hash = href.match(/#([^\?]+)/)[1]; // get id, but not any query string
        // identify destination element
        if (doc.getElementById(hash)) {
            elt = doc.getElementById(hash);
        }
        else { return true; }
        // Find scroll position to destination
        var dest = elt.offsetTop;
        for (var node = elt;
			node.offsetParent && node.offsetParent != doc.body;
			node = node.offsetParent,
			dest += node.offsetTop);
        // fix for stupid IE
        if (navigator.appName.indexOf("Microsoft") != -1
				&& parseFloat(navigator.appVersion.split("MSIE")[1]) < 8.0) {
            dest = elt.offsetTop;
        }
        clearTimeout(timer);
        var start = window.pageYOffset || doc.documentElement.scrollTop || doc.body.scrollTop;
        // fix for back button
        location.hash = hash;     // jump to destination
        window.scrollTo(0, start); // then quickly jump back to scroll the distance
        var speed = parseInt(Math.abs(start - dest) / scrollSpeed);
        Scroll(speed, (dest - 10));   // minus 10 for padding
    };
    Scroll = function (step, desty) {
        var doc = document;
        was = window.pageYOffset || doc.documentElement.scrollTop || doc.body.scrollTop;
        // find out how much to scroll by up/down
        var amt = (was < desty) ? was + step : was - step;
        // Make sure we didn't go past
        if (Math.abs(was - desty) < step) {
            amt = desty;
        }
        window.scrollTo(0, amt);
        now = window.pageYOffset || doc.documentElement.scrollTop || doc.body.scrollTop;
        // slow scroll down as approach
        var diff = Math.abs(now - desty);
        if (diff < 1) { step = 1; }
        else if (diff < step * 2) { step *= .6; }
        else if (diff < step * 6) { step *= .9; }
        // if we're at the right scroll position
        if (was == now) {
            window.scrollTo(0, desty);
            clearTimeout(timer); // clear interval
            if (shine) {
                setTimeout(function () { ShineOn(); }, 400);
            }
            return;
        }
        timer = setTimeout(function () {
            Scroll(step, desty);
        }, 30);
    };
    ShineOn = function () {
        var c = elt.style.backgroundColor;
        var o = elt.style.outline;
        elt.style.backgroundColor = shineColor;
        elt.style.outline = '1px solid ' + shineOutline;
        setTimeout(function () { ShineOff(c, o); }, 1000);
    };
    ShineOff = function (oldColor, oldOutline) {
        elt.style.backgroundColor = oldColor;
        elt.style.outline = oldOutline;
    };
    // Classic append for onload event to avoid overriding
    function appendOnLoad(fx) {
        try { // For browsers that know DOMContentLoaded (FF, Safari, Opera)
            document.addEventListener('DOMContentLoaded', fx, false);
        } catch (e) { // for IE and older browser
            try {
                document.addEventListener('load', fx, false);
            }
            catch (ee) {
                window.attachEvent('onload', fx);
            }
        }
    }
    appendOnLoad(Init);
    return {
        Setup: Setup
    };
} ();