var DDSPEED = 5;
var DDTIMER = 15;

function changeDiv(wdiv) {
	document.getElementById("dropdown").setAttribute("class", "over");
}

// 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,h);}, 50);
    }
}

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

// 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');
  h.className ="over";
  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 * 1;
  c.style.filter = 'alpha(opacity=' + (currh * 100 / c.maxh) * 1 + ')';
  if((currh < 2 && d != 1) || (currh > (c.maxh - 2) && d == 1)){
    clearInterval(c.timer);
  }
}