var DDSPEED = 10;
var DDTIMER = 15;

// main function to handle the mouse events //
function ddMenu(id,d){
  var h = document.getElementById(id + '-header');
  var c = document.getElementById(id + '-nav');
  var c2= document.getElementById('nav_box'); 
  var c3= document.getElementById('one-header'); 
  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 = 180; //c.offsetHeight;
      c.style.height = '0px';
    }
    c.timer = setInterval(function(){ddSlide(c,c2,c3,1)},DDTIMER);
  }else{
    h.timer = setTimeout(function(){ddCollapse(c,c2,c3)},50);
  }
}

// collapse the menu //
function ddCollapse(c,c2,c3){
  c.timer = setInterval(function(){ddSlide(c,c2,c3,-1)},DDTIMER);
}

// cancel the collapse if a user rolls over the dropdown //
function cancelHide(id){
  var h = document.getElementById(id + '-header');
  var c = document.getElementById(id + '-nav');
  var c2=  document.getElementById('nav_box'); 
  var c3= document.getElementById('one-header'); 
  clearTimeout(h.timer);
  clearInterval(c.timer);
  if(c.offsetHeight < c.maxh){
    c.timer = setInterval(function(){ddSlide(c,c2,c3,1)},DDTIMER);
  }
}

// incrementally expand/contract the dropdown and change the opacity //
function ddSlide(c,c2,c3,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'; 
  c2.style.height = c.style.height;
  c3.style.height = c.style.height;
  if(c.style.height == "4px"){
	document.getElementById('one-header').style.height = "0px";
	document.getElementById('one-nav').style.height = "0px";  
  }
  if((currh < 2 && d != 1) || (currh > (c.maxh - 2) && d == 1)){		
    clearInterval(c.timer);
  }
}