active_dropdown = -1;
dropdown_over = 0;
dropdown_timer = 0;
function show_dropdown(that,key,up)
{
    if(that)
    {
    var e = document.getElementById("dropdown_"+active_dropdown);
    if(e) e.style.display = "none";

    var e = document.getElementById("dropdown_"+key);
    if(!e) return;
    e.style.display = "block";
    var pos = get_element_position(that);
    e.style.left = pos.left;
    e.style.top = pos.top+20;


    active_dropdown = key;
    dropdown_over = 1;
    }

    dropdown_timer = 20;
}

function hide_dropdown()
{
    dropdown_over = 0;
}

function dropdown_tick()
{
    if(!dropdown_over)dropdown_timer--;
    if(dropdown_timer<=0)
    {
        var e = document.getElementById("dropdown_"+active_dropdown);
        if(e) e.style.display = "none";
    }
}
setInterval(dropdown_tick,50);

function get_element_position(e)
{
    var left = 0;
    var top = 0;
    while(e) {
        left += e.offsetLeft;
        top += e.offsetTop;
        e = e.offsetParent; } 
    return { left:left,top:top }
}