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 / 1.1;

  c.style.filter = 'alpha(opacity=' + (currh * 100 / c.maxh / 1.1) + ')';

  if((currh < 2 && d != 1) || (currh > (c.maxh - 2) && d == 1)){

    clearInterval(c.timer);

  }
}