// 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)

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

// 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 anchor on this page
                if ( anchors[i].href.indexOf("#") != -1)
                {
                        // get name of target anchor
                        targ = anchors[i].href.substring( anchors[i].href.indexOf("#")+1 );

                        // find target anchor
                        targarr = document.getElementsByName( targ );

                        if (targarr.length)
                        {
                                anchors[i].className = (targarr[0].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 anchors, i, ele, elePosY, heightCorrection;

        if (!document.getElementById)
                return;

        // get anchor
        anchors = document.getElementsByTagName("a");
        for (i=0;i<anchors.length;i++) {
                if (anchors[i].name == aname) {
                        ele = anchors[i];
                        i = anchors.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 = 30;

        // 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 = 10;

        // 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;
}