var a = Math.floor(Math.random()*9999999999+1) 
var random_number = a; 

var $hide = Array();

function show_layer($id)
{
    $hide[$id] = false;
    $obj = document.getElementById($id);
    $obj.style.visibility = 'visible';
}
function hide_layer($id)
{
    $hide[$id] = true;
    window.setTimeout('do_hide_layer("'+$id+'")',10);
}
function do_hide_layer($id)
{
    $obj = document.getElementById($id);
    if ($hide[$id])
    {
        $obj.style.visibility = 'hidden';
    }
}