var timerlen = 5;
var slideAniLen = 400;
var timerID = new Array();
var startTime = new Array();
var obj = new Array();
var endHeight = new Array();
var dir = new Array();
var currentMenu = '';
var currentMenuHeight = '';

function doMenu(objname, mheight) {
  if (currentMenu != objname) {
    if (currentMenu != '' && currentMenuHeight != 0) {
		slideup(currentMenu,currentMenuHeight);
    }	  
    if (mheight != 0) {
		slidedown(objname,mheight);
	}
    currentMenu = objname;
	currentMenuHeight = mheight;
  }	else {
    if (currentMenu != '' && currentMenuHeight != 0) {
      slideup(currentMenu,currentMenuHeight);
      currentMenu = '';
    }	  
  }

}

function slidedown(objname,mheight){
  if(document.getElementById(objname).style.display != "none")
	return; // cannot slide down something that is already visible

  dir[objname] = "down";
  startslide(objname,mheight);
}

function slideup(objname,mheight){

  if(document.getElementById(objname).style.display == "none")
     return; // cannot slide up something that is already hidden

  dir[objname] = "up";
  startslide(objname,mheight);
}

function startslide(objname,mheight){
  clearInterval(timerID[objname]);
  obj[objname] = document.getElementById(objname);

  endHeight[objname] = parseInt(mheight);
  startTime[objname] = (new Date()).getTime();

  if(dir[objname] == "down"){
    obj[objname].style.height = "1px";
  }
  obj[objname].style.display = "block";
  timerID[objname] = setInterval('slidetick(\'' + objname + '\');',timerlen);
}

function slidetick(objname){
  var elapsed = (new Date()).getTime() - startTime[objname];

  if (elapsed > slideAniLen) {
    endSlide(objname)
  } else {
    var d =Math.round(elapsed / slideAniLen * endHeight[objname]);
    if(dir[objname] == "up")
      d = endHeight[objname] - d;
      obj[objname].style.height = d + "px";
   }
  return;
}

function endSlide(objname){
  clearInterval(timerID[objname]);

  if(dir[objname] == "up")
    obj[objname].style.display = "none";

  obj[objname].style.height = endHeight[objname] + "px";

  delete(timerID[objname]);
  delete(startTime[objname]);
  delete(endHeight[objname]);
  delete(obj[objname]);
  delete(dir[objname]);
  return;
}