//This is the file that is responsible for sliding navigation items up and down.
//The function to call is toggleSlide(LayerName) where LayerName is the id of the layer you wish to show/hide
//The function automatically determines if the layer should slide up or down
//The first two variables below control the spead and framerate of the animation

var timerlen = 5;
var slideAniLen = 200;

var timerID = new Array();
var startTime = new Array();
var obj = new Array();
var endHeight = new Array();
var moving = new Array();
var dir = new Array();

function slidedown(objname){
        if(moving[objname])
                return;

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

        moving[objname] = true;
        dir[objname] = "down";
        startslide(objname);
}

function slideup(objname){
        if(moving[objname])
                return;

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

        moving[objname] = true;
        dir[objname] = "up";
        startslide(objname);
}


function startslide(objname){
		obj[objname] = document.getElementById(objname);
		obj[objname].style.display = "block";
		endHeight[objname] = parseInt(obj[objname].offsetHeight);
		obj[objname].style.display = "none";
		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 = "auto";

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


        return;
}

function toggleSlide(objname){
  if(document.getElementById(objname).style.display == "none"){
    // div is hidden, so let's slide down
    slidedown(objname);
  }else{
    // div is not hidden, so slide up
    slideup(objname);
  }
}