function getWindowHeight() 
{
    var windowHeight=0;
    if (typeof(window.innerHeight) == 'number') 
    {
        windowHeight=window.innerHeight;
    }
    else 
    {
        if (document.documentElement && document.documentElement.clientHeight) 
        {
            windowHeight=document.documentElement.clientHeight;
        }
        else 
        {
            if (document.body&&document.body.clientHeight) 
            {
                windowHeight=document.body.clientHeight;
            }
        }
    }
    return windowHeight;
}
function setFooter() 
{
    if (document.getElementById) 
    {
        var windowHeight=getWindowHeight();
        if (windowHeight > 0) 
        {
            var contentHeight = document.getElementById('contentBody').offsetHeight;
            var headerHeight = document.getElementById('header').offsetHeight;
            var footerElement = document.getElementById('footer');
            var footerHeight = footerElement.offsetHeight;
            if (windowHeight - (contentHeight + footerHeight + headerHeight) >= 0) 
            {
                footerElement.style.position='relative';
                footerElement.style.top = (windowHeight - (contentHeight + footerHeight + headerHeight)) + 'px';
            }
            else 
            {
                footerElement.style.position='static';
            }
        }
    }
}
window.onload = function() 
{
    setFooter();
}

window.onresize = function() 
{
    setFooter();
}