var DropDownMenu_SPEED = 10;
var DropDownMenu_TIMER = 15;


//-----------------------------------------------------------------------------
// main function to handle the mouse events
//
function DropDownMenu_Menu(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() {DropDownMenu_Slide(c,1)}, DropDownMenu_TIMER);
  } else {
    h.timer = setTimeout(function() {DropDownMenu_Collapse(c)}, 50);
  }
}


//-----------------------------------------------------------------------------
// collapse the menu
//
function DropDownMenu_Collapse(c) {
  c.timer = setInterval(function() {DropDownMenu_Slide(c,-1)}, DropDownMenu_TIMER);
}


//-----------------------------------------------------------------------------
// cancel the collapse if a user rolls over the dropdown
//
function DropDownMenu_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() {DropDownMenu_Slide(c,1)}, DropDownMenu_TIMER);
  }
}


//-----------------------------------------------------------------------------
// incrementally expand/contract the dropdown and change the opacity
//
function DropDownMenu_Slide(c,d) {
  var currh = c.offsetHeight;
  var dist;

  if (d == 1) {
    dist = (Math.round((c.maxh - currh) / DropDownMenu_SPEED));
  } else {
    dist = (Math.round(currh / DropDownMenu_SPEED));
  }

  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 * 100 / c.maxh) + ')';

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