/* Script by: www.jtricks.com
 * Version: 20071017
 * Latest version:
 * www.jtricks.com/javascript/navigation/floating.html
 */
var shfloatingMenuId = 'shfloatdiv';
var shfloatingMenu =
{
    targetX: 300,
    targetY: 200,

    hasInner: typeof(window.innerWidth) == 'number',
    hasElement: typeof(document.documentElement) == 'object'
        && typeof(document.documentElement.clientWidth) == 'number',

    menu:
        document.getElementById
        ? document.getElementById(shfloatingMenuId)
        : document.all
          ? document.all[shfloatingMenuId]
          : document.layers[shfloatingMenuId]
};

shfloatingMenu.move = function ()
{
    shfloatingMenu.menu.style.left = shfloatingMenu.nextX + 'px';
    shfloatingMenu.menu.style.top = shfloatingMenu.nextY + 'px';
}

shfloatingMenu.computeShifts = function ()
{
    var de = document.documentElement;

    shfloatingMenu.shiftX =  
        shfloatingMenu.hasInner  
        ? pageXOffset  
        : shfloatingMenu.hasElement  
          ? de.scrollLeft  
          : document.body.scrollLeft;  
    if (shfloatingMenu.targetX < 0)
    {
        shfloatingMenu.shiftX +=
            shfloatingMenu.hasElement
            ? de.clientWidth
            : document.body.clientWidth;
    }

    shfloatingMenu.shiftY = 
        shfloatingMenu.hasInner
        ? pageYOffset
        : shfloatingMenu.hasElement
          ? de.scrollTop
          : document.body.scrollTop;
    if (shfloatingMenu.targetY < 0)
    {
        if (shfloatingMenu.hasElement && shfloatingMenu.hasInner)
        {
            // Handle Opera 8 problems
            shfloatingMenu.shiftY +=
                de.clientHeight > window.innerHeight
                ? window.innerHeight
                : de.clientHeight
        }
        else
        {
            shfloatingMenu.shiftY +=
                shfloatingMenu.hasElement
                ? de.clientHeight
                : document.body.clientHeight;
        }
    }
}

shfloatingMenu.calculateCornerX = function()
{
    if (shfloatingMenu.targetX != 'center')
        return shfloatingMenu.shiftX + shfloatingMenu.targetX;

    var width = parseInt(shfloatingMenu.menu.offsetWidth);

    var cornerX =
        shfloatingMenu.hasElement
        ? (shfloatingMenu.hasInner
           ? pageXOffset
           : document.documentElement.scrollLeft) + 
          (document.documentElement.clientWidth - width)/2
        : document.body.scrollLeft + 
          (document.body.clientWidth - width)/2;
    return cornerX;
};

shfloatingMenu.calculateCornerY = function()
{
    if (shfloatingMenu.targetY != 'center')
        return shfloatingMenu.shiftY + shfloatingMenu.targetY;

    var height = parseInt(shfloatingMenu.menu.offsetHeight);

    // Handle Opera 8 problems
    var clientHeight = 
        shfloatingMenu.hasElement && shfloatingMenu.hasInner
        && document.documentElement.clientHeight 
            > window.innerHeight
        ? window.innerHeight
        : document.documentElement.clientHeight

    var cornerY =
        shfloatingMenu.hasElement
        ? (shfloatingMenu.hasInner  
           ? pageYOffset
           : document.documentElement.scrollTop) + 
          (clientHeight - height)/2
        : document.body.scrollTop + 
          (document.body.clientHeight - height)/2;
    return cornerY;
};

shfloatingMenu.doFloat = function()
{
    // Check if reference to menu was lost due
    // to ajax manipuations
    if (!shfloatingMenu.menu)
    {
        menu = document.getElementById
            ? document.getElementById(shfloatingMenuId)
            : document.all
              ? document.all[shfloatingMenuId]
              : document.layers[shfloatingMenuId];

        initSecondary();
    }

    var stepX, stepY;

    shfloatingMenu.computeShifts();

    var cornerX = shfloatingMenu.calculateCornerX();

    var stepX = (cornerX - shfloatingMenu.nextX) * .07;
    if (Math.abs(stepX) < .5)
    {
        stepX = cornerX - shfloatingMenu.nextX;
    }

    var cornerY = shfloatingMenu.calculateCornerY();

    var stepY = (cornerY - shfloatingMenu.nextY) * .07;
    if (Math.abs(stepY) < .5)
    {
        stepY = cornerY - shfloatingMenu.nextY;
    }

    if (Math.abs(stepX) > 0 ||
        Math.abs(stepY) > 0)
    {
        shfloatingMenu.nextX += stepX;
        shfloatingMenu.nextY += stepY;
        shfloatingMenu.move();
    }

    setTimeout('shfloatingMenu.doFloat()', 20);
};

// addEvent designed by Aaron Moore
shfloatingMenu.addEvent = function(element, listener, handler)
{
    if(typeof element[listener] != 'function' || 
       typeof element[listener + '_num'] == 'undefined')
    {
        element[listener + '_num'] = 0;
        if (typeof element[listener] == 'function')
        {
            element[listener + 0] = element[listener];
            element[listener + '_num']++;
        }
        element[listener] = function(e)
        {
            var r = true;
            e = (e) ? e : window.event;
            for(var i = element[listener + '_num'] -1; i >= 0; i--)
            {
                if(element[listener + i](e) == false)
                    r = false;
            }
            return r;
        }
    }

    //if handler is not already stored, assign it
    for(var i = 0; i < element[listener + '_num']; i++)
        if(element[listener + i] == handler)
            return;
    element[listener + element[listener + '_num']] = handler;
    element[listener + '_num']++;
};

shfloatingMenu.init = function()
{
    shfloatingMenu.initSecondary();
    shfloatingMenu.doFloat();
};

// Some browsers init scrollbars only after
// full document load.
shfloatingMenu.initSecondary = function()
{
    shfloatingMenu.computeShifts();
    shfloatingMenu.nextX = shfloatingMenu.calculateCornerX();
    shfloatingMenu.nextY = shfloatingMenu.calculateCornerY();
    shfloatingMenu.move();
}

if (document.layers)
    shfloatingMenu.addEvent(window, 'onload', shfloatingMenu.init);
else
{
    shfloatingMenu.init();
    shfloatingMenu.addEvent(window, 'onload',
        shfloatingMenu.initSecondary);
}