function scrollBackground() { 
    // v1.1 Disables background screen scrolling while viewing shadowbox popups 

    // Copyright 2010 Peter Smith - The Science Registry 
    // Usage: Allowed if copyright statement remains 

    // add the following to the Shadowbox.init ({}) 
    // onOpen: scrollBackground, onClose: scrollBackground 

    // Get a reference to the HTML element 
    var objHTML = document.getElementsByTagName("html").item(0); 

    // Hide/show scrollbar 
    if (objHTML.style.overflow == "hidden") { 
        objHTML.style.overflow = "auto"; 
        $(window).scrollTop(_scrollTop); 
    } else { 
        _scrollTop = $(window).scrollTop(); 
        objHTML.style.overflow = "hidden"; 
        // Hiding the vertical scrollbar and having the webpage centered makes the content jump across by the amount of the scrollbars width 
        // this adjust that if html width is not set i.e. it only fires once. 
        if (objHTML.style.width == "") objHTML.style.width = "" + parseInt(objHTML.offsetWidth - 17) + "px"; 
    } 
}