var DDSPEED = 10;
var DDTIMER = 15;

// main function to handle the mouse events //
function ddMenu(id,dir) {
  var head = document.getElementById(id + '-ddheader');
  var cont = document.getElementById(id + '-ddcontent');
  clearInterval(cont.timer);
  if(dir == 1) {
    clearTimeout(head.timer);
    if(cont.maxh && cont.maxh <= cont.offsetHeight) {
      return;
    } else if(!cont.maxh) {
      cont.style.display = 'block';
      cont.style.height = 'auto';
      cont.maxh = cont.offsetHeight;
      cont.style.height = '0px';
    }
    cont.timer = setInterval("ddSlide('" + id + "-ddcontent', 1)", DDTIMER);
  } else {
    head.timer = setTimeout('ddCollapse(\'' + id + '-ddcontent\')', 50);
  }
}

// collapse the menu //
function ddCollapse(id) {
  var cont = document.getElementById(id);
  //alert('ddCollapse('+id+')'+cont);
  cont.timer = setInterval("ddSlide('" + id + "', -1)", DDTIMER);
}

// cancel the collapse if a user rolls over the dropdown content //
function cancelHide(id) {
  var head = document.getElementById(id + '-ddheader');
  var cont = document.getElementById(id + '-ddcontent');
  clearTimeout(head.timer);
  clearInterval(cont.timer);
  if(cont.offsetHeight < cont.maxh) {
    cont.timer = setInterval("ddSlide('" + id + "-ddcontent', 1)", DDTIMER);
  }
}

// incrementally expand/contract the dropdown and change the opacity //
function ddSlide(id,dir) {
	//alert('ddSlide'+dir);
	var cont = document.getElementById(id);
	var currheight = cont.offsetHeight;
	var dist;
	if(dir == 1) {
		dist = (Math.round((cont.maxh - currheight) / DDSPEED));
	} else {
		dist = (Math.round(currheight / DDSPEED));
	}
	if(dist <= 1 && dir == 1) {
		dist = 1;
	}
	cont.style.height = currheight + (dist * dir) + 'px';
	cont.style.opacity = currheight / cont.maxh;
	cont.style.filter = 'alpha(opacity=' + (currheight * 100 / cont.maxh) + ')';

	/* RB Fix for persistent semi transparent dropdowns on FF */
	if ( dir == -1 && currheight < 30 ){
		//alert("HERE");
		cont.style.opacity = 0;
		cont.style.mozopacity = 0;
		cont.style.filter = 'alpha(opacity=' + 0 + ')';
		clearInterval(cont.timer);
	}
	
	if((currheight < 2 && dir != 1) || (currheight > (cont.maxh - 2) && dir == 1)) {
		//alert("currheight="+currheight);
		clearInterval(cont.timer);
	}
}