function getViewPortWidth()
{
    if(typeof(window.innerWidth) == 'number')//Non-IE
        return window.innerWidth;
    else if(document.documentElement && (document.documentElement.clientWidth ||
            document.documentElement.clientHeight))//IE 6+ in 'standards compliant mode'
        return document.documentElement.clientWidth;
    else if(document.body && (document.body.clientWidth || document.body.clientHeight))//IE 4 compatible
        return document.body.clientWidth;
    else return 0;
}