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(120 / DDSPEED));
  }
  if(dist <= 1 && d == 1){
    dist = 1;
  }
  c.style.height = currh + (dist * d) + 'px';
  c.style.opacity = currh / c.maxh;
  c.style.filter = 'alpha(opacity=' + (currh * 80 / c.maxh) + ')';
  if((currh < 2 && d != 1) || (currh > (c.maxh - 2) && d == 1)){
    clearInterval(c.timer);
  }
}

// Swap the fields appearing, based on menu selection.
function switchSearchFields( field )	{

	document.getElementById('rest_search').style.display='none';
	document.getElementById('night_search').style.display='none';
	document.getElementById('hotel_search').style.display='none';
	document.getElementById('city_search').style.display='none';
	document.getElementById(field).style.display='block';

	switch(field)	{
		case 'city_search':
				document.getElementById('one-ddheader').innerHTML = 'Select a City <img src="/images/twisty_right.png">';
			break;
		case 'rest_search':
				document.getElementById('one-ddheader').innerHTML = 'Search for a Restaurant <img src="/images/twisty_right.png">';
			break;
		case 'night_search':
				document.getElementById('one-ddheader').innerHTML = 'Search for a Nightspot <img src="/images/twisty_right.png">';
			break;
		case 'hotel_search':
				document.getElementById('one-ddheader').innerHTML = 'Search for a Hotel <img src="/images/twisty_right.png">';
			break;
		default:
				document.getElementById('one-ddheader').innerHTML = 'Search for a ... <img src="/images/twisty_down.png">';
	}
	ddMenu('one',-1);
	
	return false;
}