var timerlen = 15;
var slideAniLen = 300;
//var factor = 0; // no animation (last script behaviour)
//var factor = 1; // normal animation (lineal, this script)
//var factor = 2; // accelerated animation (retarded)
var factor = 3; // fast (i use this)
//var factor = 0.5 // fast animation, but slower at the end (nice effect! =) )


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);

        //endHeight[objname] = parseInt(obj[objname].style.height);
        if(obj[objname].clientHeight != 0)
				endHeight[objname] = obj[objname].clientHeight;
		else
				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 timeratio = (elapsed / slideAniLen);
		timeratio = Math.pow(timeratio,factor);
		
		var d =Math.round( timeratio * endHeight[objname]);
		
		if(dir[objname] == "up")
		
		d = endHeight[objname] - d;
		
		obj[objname].style.height = d + "px";
		
		}
		
		return;

}
/*
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(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);
    return false;
  }else{
    // div is not hidden, so slide up
    slideup(objname);
    return false;
  }
}