var dropdown_intervalId;
var dropdown_ulId = (!dropdown_ulId) ? 'nav' : dropdown_ulId;
var dropdown_delay = (!dropdown_delay) ? 0 : dropdown_delay;

function dropdown_init()
{
 try
 {
  var as = document.getElementById(dropdown_ulId).getElementsByTagName('a');

  for (var a = 0; a < as.length; a++)
  {
   as[a].onfocus = function() { dropdown_expand(this) }
   as[a].onmouseover = function() { dropdown_expand(this) }
   as[a].onblur = function() { dropdown_colapse(dropdown_delay) }
   as[a].onmouseout = function() { dropdown_colapse(dropdown_delay) }
  }

  dropdown_colapse(0);

 } catch(e){}

}

function dropdown_expand(caller)
{
 try
 {
  clearInterval(dropdown_intervalId);

  var uls = caller.parentNode.parentNode.getElementsByTagName('ul');

  for (var ul = 0; ul < uls.length; ul++)
   uls[ul].style.left = "-1000em";

  caller.parentNode.getElementsByTagName('ul')[0].style.left = "auto";

 } catch(e){}

}

function dropdown_colapse(milliseconds)
{
 try
 {
  clearInterval(dropdown_intervalId);

  dropdown_intervalId = setInterval(function()
  {
   var uls = document.getElementById(dropdown_ulId).getElementsByTagName('ul');

   for (var ul = 0; ul < uls.length; ul++)
    uls[ul].style.left = "-1000em";

   clearInterval(dropdown_intervalId);

  }, milliseconds, null);

 } catch(e){}

}

window.onload = dropdown_init;

/* thanks to http://www.felipealbuquerque.com/2009/10/19/menu-drop-down-acessivel/ */