var active_sub = "";
var margin_top = 0;
var margin_const = 305; 

function str_replace(search,replace,subject){var s=subject;var ra=r instanceof Array,sa=s instanceof Array;var f=[].concat(search);var r=[].concat(replace);var i=(s=[].concat(s)).length;var j=0;while(j=0,i--){if(s[i]){while(s[i]=(s[i]+'').split(f[j]).join(ra?r[j]||"":r[0]),++j in f){};}}
return sa?s:s[0];}

function show_sub(id, active)
{
   if(active == true) active_sub = id;
   if(active == false) active_sub = id+"_sub";
   var submenu = document.getElementById(active_sub);
   var menu_name = str_replace("_sub", "", active_sub);
   var menu = document.getElementById(menu_name);

   margin_top = menu.offsetTop - margin_const;
   submenu.style.marginTop = margin_top+"px";
   submenu.style.display = "block";
}

function hide_sub()
{
   var submenu = document.getElementById(active_sub);
   active_sub = "";
   margin_top = 0;
   submenu.style.display = "none";
}