function slide(Id, interval, to) { 
    var obj = document.getElementById(Id); 
    var H, step = 5; 

    if (obj == null) return; 
    if (to == undefined) { // user clicking 
        if (obj._slideStart == true) return; 
        if (obj._expand == true) { 
            to = 0; 
            obj.style.overflow = "hidden"; 
        } else { 
            slide.addId(Id); 
            for(var i=0; i < slide.objects.length; i++) { 
                if (slide.objects[i].id != Id && slide.objects[i]._expand == true) { 
                    slide(slide.objects[i].id); 
                } 
            } 

            obj.style.height = ""; 
            obj.style.overflow = ""; 
            obj.style.display = "block"; 
            to = obj.offsetHeight; // 이거이거 
            obj.style.overflow = "hidden"; 
            obj.style.height = "1px"; 
        } 
        obj._slideStart = true; 
    } 
    
    step            = ((to > 0) ? 1:-1) * step; 
    interval        = ((interval==undefined)?1:interval); 

    obj.style.height = (H=((H=(isNaN(H=parseInt(obj.style.height))?0:H))+step<0)?0:H+step)+"px"; 
    
    
    if (H <= 0) { 
        obj.style.display = "none"; 
        obj.style.overflow = "hidden"; 
        obj._expand = false; 
        obj._slideStart = false; 
    } else if (to > 0 && H >= to) { 
        obj.style.display = "block"; 
        obj.style.overflow = "visible"; 
        obj.style.height = H + "px"; 
        obj._expand = true; 
        obj._slideStart = false; 
    } else { 
        setTimeout("slide('"+Id+"' , "+interval+", "+to+");", interval); 
    } 
} 
slide.objects = new Array(); 
slide.addId = function(Id) { 
    for (var i=0; i < slide.objects.length; i++) { 
        if (slide.objects[i].id == Id) return true; 
    } 
    slide.objects[slide.objects.length] = document.getElementById(Id); 
}