var activesubmenu = null;
var coverDiv = null;

function showsubmenu(d) {
    var id = d.id.split("_")[1];
    var sub = document.getElementById("submenu_"+id);
    if (sub==activesubmenu) {
        return;
    }
    hidesubmenu();

    if (sub) {
        activesubmenu = sub;
        activesubmenu.style.display = "block";
        var pos = getXYOf(d);
        var y = pos.y + d.offsetHeight;
        sub.style.left = pos.x + "px";
        sub.style.top =  y + "px";

        coverDiv = document.getElementById("coverDiv");
        y+=24;
        coverDiv.style.top = y+"px";
        var h = document.body.offsetHeight - y - 30;
        coverDiv.style.height = (h>=1?h:1) +"px";
        coverDiv.style.left = "0px";
        coverDiv.style.width = "100%";
        coverDiv.style.display = "block";
    }

}
function hidesubmenu() {
    if (activesubmenu) {
        activesubmenu.style.display = "none";
        coverDiv.style.display = "none";
        activesubmenu = null;
    }
}
function getXYOf(a) {
   var r=new Object();
   if (a==document.body) {
      r.x=0;
      r.y=0;
      return r;
   }
   p = getXYOf(a.offsetParent);
   r.x = a.offsetLeft+p.x;
   r.y = a.offsetTop+p.y;
   return r;
}