var DDSPEED = 5;
var DDTIMER = 10;

function ddMenu_(id){
	var c = document.getElementById(id);
	if(c.offsetHeight<10){
		ddMenu(id,1);
		document.getElementById(id + '_link').style.color="white";
	} else {
		ddMenu(id,-1);
		document.getElementById(id + '_link').style.color="";
	}
	
}
function ddMenu(id,d){
  var c = document.getElementById(id);
  clearInterval(c.timer);
  if(d == 1){
    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{
    ddCollapse(c);
  }

}

function ddCollapse(c){
  c.timer = setInterval(function(){ddSlide(c,-1)},DDTIMER);
}

function cancelHide(id){
  var c = document.getElementById(id);
  clearInterval(c.timer);
  if(c.offsetHeight < c.maxh){
    c.timer = setInterval(function(){ddSlide(c,1)},DDTIMER);
  }
}

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';
  if (d==-1 && currh + (dist * d)<10){
	c.style.height="0px";
	clearInterval(c.timer);
  }
  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);
  }
}