var timerlen = 5;
var slideAniLen = 500;

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

function slidedown(objname, height){
        if(moving[objname])
                return;
        
        if(document.getElementById(objname).clientHeight > (height-20)) {
        	            return; // cannot slide down something that is already visible
        }
        moving[objname] = true;
        dir[objname] = "down";
        startslide(objname, height, 0);
}

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

        if(document.getElementById(objname).clientHeight <= minHeight)
                return; // cannot slide up something that is already hidden
        
        moving[objname] = true;
        dir[objname] = "up";
        
        minHeightTot = minHeight;
        
        startslide(objname, height);
}

function startslide(objname, target){
        obj[objname] = document.getElementById(objname);

        actualHeight = parseInt(obj[objname].style.height);
        
        endHeight[objname] = target;
        startTime[objname] = (new Date()).getTime();
        
        if(dir[objname] == "down"){
                obj[objname].style.height = (actualHeight+1) + "px";
        }

        //obj[objname].style.display = "block";

        timerID[objname] = setInterval('slidetick(\'' + objname + '\');',timerlen);
}

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

        if ((elapsed > slideAniLen)||((document.getElementById(objname).clientHeight <= minHeightTot)&&(dir[objname]=="up")))
                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.height = minHeightTot + "px";
        } else {
        	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;
}