var timerlen = 5;
var slideAniLen = 250;

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

/**
Usage scroll up or down a div.
name - string - the id of the div.
callback - function - called before and after evey action

set the callback to null if you don't use them.

define callback as follows



function callback(action, state)
where 
action  == "down" - the div is opeingin
action  == "up"  - the div is closing
state == "start" - the action is about to start
state == "end" - the action is finished.

**/

function scrollArea(name, callback, height) {
	callbackfunction = callback;
	if (document.getElementById) {  
 		var div = document.getElementById(name);
 		if (div.style.display=='none') {
 			div.style.height = height;
 			if (callbackfunction != null)
 				callbackfunction("down", "start")
 			slidedown(name);
  		} else {
 			if (callbackfunction != null)
 				callbackfunction("up", "start")
			slideup(name);
 		}
	}
}

function setScrollHeight(name, height) {
	if (document.getElementById) {  
 		var div = document.getElementById(name);
 		if (div.style.display!='none') {
 			div.style.height = height;
  		} else {
 		}
	}
}
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);

        endHeight[objname] = parseInt(obj[objname].style.height);
        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";
 			if (callbackfunction != null)
 				callbackfunction("up", "end")
        } else {
  			if (callbackfunction != null)
 				callbackfunction("down", "end");
        }

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

        delete(moving[objname]);
        delete(timerID[objname]);
        delete(startTime[objname]);
        delete(endHeight[objname]);
        delete(obj[objname]);
        delete(dir[objname]);
		if (callbackfunction != null)
			callbackfunction();
        return;
}