var DDSPEED = 4;
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, h) }, DDTIMER);
    
   } else {
   h.timer = setTimeout(function() { ddCollapse(c,h) }, 50);
   
  }
}

// collapse the menu //
function ddCollapse(c,h){
	c.timer = setInterval(function() { ddSlide(c, -1,h) }, DDTIMER);
	//h.className = "";
}

// 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,h)},DDTIMER);
  }
}

// incrementally expand/contract the dropdown and change the opacity //
function ddSlide(c, d, h) {
	
  var currh = c.offsetHeight;
  var dist;
  if(d == 1){
  	dist = (Math.round((c.maxh - currh) / DDSPEED));
  	h.className = "current";
  }else{
  dist = (Math.round(currh / DDSPEED));
  h.className = "";
  }
  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);
  }
}