function centerIntro()
{
    screenWidth = document.getElementById("body").offsetWidth;
    screenHeight = document.getElementById("body").offsetHeight;
    document.getElementById("intro").style.height = screenHeight + "px";
    if (navigator.userAgent.indexOf('Firefox') != -1)
    {
        document.getElementById("intro").style.width = screenWidth-16 + "px";
    }
    else
    {
        document.getElementById("intro").style.width = screenWidth + "px";
    }
}

var TimeToFade = 1000.0;

function fade(what)
{
    var element = document.getElementById(what);
    if(element == null)
        return;
   
    if(element.FadeState == null)
    {
        if(element.style.opacity == null
            || element.style.opacity == ''
            || element.style.opacity == '1')
        {
            element.FadeState = 2;
        }
        else
        {
            element.FadeState = -2;                    
        }
    }
    
    if(element.FadeState == 1 || element.FadeState == -1)
    {
        element.FadeState = element.FadeState == 1 ? -1 : 1;
        element.FadeTimeLeft = TimeToFade - element.FadeTimeLeft;
    }
    else
    {
        element.FadeState = element.FadeState == 2 ? -1 : 1;
        element.FadeTimeLeft = TimeToFade;
        setTimeout("animateFade(" + new Date().getTime() + ",'" + what + "')", 33);
    }
}

function  animateFade(lastTick, what)
{  
    var curTick = new Date().getTime();
    var elapsedTicks = curTick - lastTick;
    
    var element = document.getElementById(what);
 
    if(element.FadeTimeLeft <= elapsedTicks)
    {
        element.style.opacity = element.FadeState == 1 ? '1' : '0';
        element.style.filter = 'alpha(opacity = '
            + (element.FadeState == 1 ? '100' : '0') + ')';
        element.FadeState = element.FadeState == 1 ? 2 : -2;
        return;
    }
    
    element.FadeTimeLeft -= elapsedTicks;
    var newOpVal = element.FadeTimeLeft/TimeToFade;
    if(element.FadeState == 1)
        newOpVal = 1 - newOpVal;
    
    element.style.opacity = newOpVal;
    element.style.filter = 'alpha(opacity = ' + (newOpVal*100) + ')';
    setTimeout("animateFade(" + curTick + ",'" + what + "')", 33);
    
    // finalizing:
    if ((!element.FadeTimeLeft) || (element.FadeTimeLeft <= 0))
    {
        showPage();hideIntro();
    }
}

function showPage()
{
    document.getElementById("page-wrapper").style.visibility = "visible";
    document.getElementById("body").style.backgroundColor = "#ffffff";
}

function hideIntro()
{
    document.getElementById("intro").style.display = "none";
    document.getElementById("intro").style.visibility = "hidden";
    document.getElementById("intro-skip").style.display = "none";
    document.getElementById("intro-skip").style.visibility = "hidden";
}