var preloadFlag = true;

function preloadImages()
{
    if(document.images && preloadFlag)
    {
        var btn_home = new Image();
        btn_home.src = "images/btn_home_hover.gif";
        var btn_mission = new Image();
        btn_mission.src = "images/btn_mission_hover.gif";
        var btn_history = new Image();
        btn_history.src = "images/btn_history_hover.gif";
        var btn_events = new Image();
        btn_events.src = "images/btn_events_hover.gif";
        var btn_pastprograms = new Image();
        btn_pastprograms.src = "images/btn_pastprograms_hover.gif";
        var btn_contributing = new Image();
        btn_contributing.src = "images/btn_contributing_hover.gif";
        var btn_subcommittees = new Image();
        btn_subcommittees.src = "images/btn_subcommittees_hover.gif";
        var btn_apply = new Image();
        btn_apply.src = "images/btn_apply_hover.gif";
        var btn_contact = new Image();
        btn_contact.src = "images/btn_contact_hover.gif";
    }
}

function changeImage(imgId, hover)
{
    //If the images wern't preloaded, don't switch them
    if(!preloadFlag)
        return;

    var img = document.getElementById(imgId);

    if(img)
    {
        if(hover)
        {
            if(img.src.match("_hover.gif") != null)
                return;
            var src = img.src;
            src = src.replace(/.gif/i, "_hover.gif");
            img.src = src;
            return;
        }
        else
        {
            var src = img.src;
            src = src.replace(/_hover.gif/i, ".gif");
            img.src = src;
            return;
        }
    }
}