var DDSPEED = 10;
var DDTIMER = 15;
// main function to handle the mouse events //
function ddMenu(id,d){
   var h = document.getElementById(id + '-ddheader');
   var c = document.getElementById(id + '-ddcontent');
   clearInterval(c.timer);
   if(d == 1){
      clearTimeout(h.timer);
      if(c.maxh && c.maxh <= c.offsetHeight)
         {return}
      else if(!c.maxh)
      {
         c.style.display = 'block';
         c.style.height = 'auto';
         c.maxh = c.offsetHeight;
         c.style.height = '0px';
      }
      c.timer = setInterval(function(){ddSlide(c,1)},DDTIMER);
   }
   else
      {h.timer = setTimeout(function(){ddCollapse(c)},50);}
}
// collapse the menu //
function ddCollapse(c){
   c.timer = setInterval(function(){ddSlide(c,-1)},DDTIMER);
}
// cancel the collapse if a user rolls over the dropdown //
function cancelHide(id){
   var h = document.getElementById(id + '-ddheader');
   var c = document.getElementById(id + '-ddcontent');
   clearTimeout(h.timer);
   clearInterval(c.timer);
   if(c.offsetHeight < c.maxh)
      {c.timer = setInterval(function(){ddSlide(c,1)},DDTIMER);}
}
// incrementally expand/contract the dropdown and change the opacity //
function ddSlide(c,d){
   var currh = c.offsetHeight;
   var dist;
   if(d == 1)
      {dist = (Math.round((c.maxh - currh) / DDSPEED));}
   else
      {dist = (Math.round(currh / DDSPEED));}
   if(dist <= 1 && d == 1)
      {dist = 1;}
   c.style.height = currh + (dist * d) + 'px';
   c.style.opacity = currh / c.maxh;
   c.style.filter = 'alpha(opacity=' + (currh * 100 / c.maxh) + ')';
   if((currh < 2 && d != 1) || (currh > (c.maxh - 2) && d == 1))
      {clearInterval(c.timer);}
}