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    Current File : /home/m/e/h/meharicl/www/recensement2/js/pt/dragdrop.js

    // script.aculo.us dragdrop.js v1.8.1, Thu Jan 03 22:07:12 -0500 2008
    
    // Copyright (c) 2005-2007 Thomas Fuchs (http://script.aculo.us, http://mir.aculo.us)
    //           (c) 2005-2007 Sammi Williams (http://www.oriontransfer.co.nz, sammi@oriontransfer.co.nz)
    // 
    // script.aculo.us is freely distributable under the terms of an MIT-style license.
    // For details, see the script.aculo.us web site: http://script.aculo.us/
    
    if(Object.isUndefined(Effect))
      throw("dragdrop.js requires including script.aculo.us' effects.js library");
    
    var Droppables = {
      drops: [],
    
      remove: function(element) {
        this.drops = this.drops.reject(function(d) { return d.element==$(element) });
      },
    
      add: function(element) {
        element = $(element);
        var options = Object.extend({
          greedy:     true,
          hoverclass: null,
          tree:       false
        }, arguments[1] || { });
    
        // cache containers
        if(options.containment) {
          options._containers = [];
          var containment = options.containment;
          if(Object.isArray(containment)) {
            containment.each( function(c) { options._containers.push($(c)) });
          } else {
            options._containers.push($(containment));
          }
        }
        
        if(options.accept) options.accept = [options.accept].flatten();
    
        Element.makePositioned(element); // fix IE
        options.element = element;
    
        this.drops.push(options);
      },
      
      findDeepestChild: function(drops) {
        deepest = drops[0];
          
        for (i = 1; i < drops.length; ++i)
          if (Element.isParent(drops[i].element, deepest.element))
            deepest = drops[i];
        
        return deepest;
      },
    
      isContained: function(element, drop) {
        var containmentNode;
        if(drop.tree) {
          containmentNode = element.treeNode; 
        } else {
          containmentNode = element.parentNode;
        }
        return drop._containers.detect(function(c) { return containmentNode == c });
      },
      
      isAffected: function(point, element, drop) {
        return (
          (drop.element!=element) &&
          ((!drop._containers) ||
            this.isContained(element, drop)) &&
          ((!drop.accept) ||
            (Element.classNames(element).detect( 
              function(v) { return drop.accept.include(v) } ) )) &&
          Position.within(drop.element, point[0], point[1]) );
      },
    
      deactivate: function(drop) {
        if(drop.hoverclass)
          Element.removeClassName(drop.element, drop.hoverclass);
        this.last_active = null;
      },
    
      activate: function(drop) {
        if(drop.hoverclass)
          Element.addClassName(drop.element, drop.hoverclass);
        this.last_active = drop;
      },
    
      show: function(point, element) {
        if(!this.drops.length) return;
        var drop, affected = [];
        
        this.drops.each( function(drop) {
          if(Droppables.isAffected(point, element, drop))
            affected.push(drop);
        });
            
        if(affected.length>0)
          drop = Droppables.findDeepestChild(affected);
    
        if(this.last_active && this.last_active != drop) this.deactivate(this.last_active);
        if (drop) {
          Position.within(drop.element, point[0], point[1]);
          if(drop.onHover)
            drop.onHover(element, drop.element, Position.overlap(drop.overlap, drop.element));
          
          if (drop != this.last_active) Droppables.activate(drop);
        }
      },
    
      fire: function(event, element) {
        if(!this.last_active) return;
        Position.prepare();
    
        if (this.isAffected([Event.pointerX(event), Event.pointerY(event)], element, this.last_active))
          if (this.last_active.onDrop) {
            this.last_active.onDrop(element, this.last_active.element, event); 
            return true; 
          }
      },
    
      reset: function() {
        if(this.last_active)
          this.deactivate(this.last_active);
      }
    }
    
    var Draggables = {
      drags: [],
      observers: [],
      
      register: function(draggable) {
        if(this.drags.length == 0) {
          this.eventMouseUp   = this.endDrag.bindAsEventListener(this);
          this.eventMouseMove = this.updateDrag.bindAsEventListener(this);
          this.eventKeypress  = this.keyPress.bindAsEventListener(this);
          
          Event.observe(document, "mouseup", this.eventMouseUp);
          Event.observe(document, "mousemove", this.eventMouseMove);
          Event.observe(document, "keypress", this.eventKeypress);
        }
        this.drags.push(draggable);
      },
      
      unregister: function(draggable) {
        this.drags = this.drags.reject(function(d) { return d==draggable });
        if(this.drags.length == 0) {
          Event.stopObserving(document, "mouseup", this.eventMouseUp);
          Event.stopObserving(document, "mousemove", this.eventMouseMove);
          Event.stopObserving(document, "keypress", this.eventKeypress);
        }
      },
      
      activate: function(draggable) {
        if(draggable.options.delay) { 
          this._timeout = setTimeout(function() { 
            Draggables._timeout = null; 
            window.focus(); 
            Draggables.activeDraggable = draggable; 
          }.bind(this), draggable.options.delay); 
        } else {
          window.focus(); // allows keypress events if window isn't currently focused, fails for Safari
          this.activeDraggable = draggable;
        }
      },
      
      deactivate: function() {
        this.activeDraggable = null;
      },
      
      updateDrag: function(event) {
        if(!this.activeDraggable) return;
        var pointer = [Event.pointerX(event), Event.pointerY(event)];
        // Mozilla-based browsers fire successive mousemove events with
        // the same coordinates, prevent needless redrawing (moz bug?)
        if(this._lastPointer && (this._lastPointer.inspect() == pointer.inspect())) return;
        this._lastPointer = pointer;
        
        this.activeDraggable.updateDrag(event, pointer);
      },
      
      endDrag: function(event) {
        if(this._timeout) { 
          clearTimeout(this._timeout); 
          this._timeout = null; 
        }
        if(!this.activeDraggable) return;
        this._lastPointer = null;
        this.activeDraggable.endDrag(event);
        this.activeDraggable = null;
      },
      
      keyPress: function(event) {
        if(this.activeDraggable)
          this.activeDraggable.keyPress(event);
      },
      
      addObserver: function(observer) {
        this.observers.push(observer);
        this._cacheObserverCallbacks();
      },
      
      removeObserver: function(element) {  // element instead of observer fixes mem leaks
        this.observers = this.observers.reject( function(o) { return o.element==element });
        this._cacheObserverCallbacks();
      },
      
      notify: function(eventName, draggable, event) {  // 'onStart', 'onEnd', 'onDrag'
        if(this[eventName+'Count'] > 0)
          this.observers.each( function(o) {
            if(o[eventName]) o[eventName](eventName, draggable, event);
          });
        if(draggable.options[eventName]) draggable.options[eventName](draggable, event);
      },
      
      _cacheObserverCallbacks: function() {
        ['onStart','onEnd','onDrag'].each( function(eventName) {
          Draggables[eventName+'Count'] = Draggables.observers.select(
            function(o) { return o[eventName]; }
          ).length;
        });
      }
    }
    
    /*--------------------------------------------------------------------------*/
    
    var Draggable = Class.create({
      initialize: function(element) {
        var defaults = {
          handle: false,
          reverteffect: function(element, top_offset, left_offset) {
            var dur = Math.sqrt(Math.abs(top_offset^2)+Math.abs(left_offset^2))*0.02;
            new Effect.Move(element, { x: -left_offset, y: -top_offset, duration: dur,
              queue: {scope:'_draggable', position:'end'}
            });
          },
          endeffect: function(element) {
            var toOpacity = Object.isNumber(element._opacity) ? element._opacity : 1.0;
            new Effect.Opacity(element, {duration:0.2, from:0.7, to:toOpacity, 
              queue: {scope:'_draggable', position:'end'},
              afterFinish: function(){ 
                Draggable._dragging[element] = false 
              }
            }); 
          },
          zindex: 1000,
          revert: false,
          quiet: false,
          scroll: false,
          scrollSensitivity: 20,
          scrollSpeed: 15,
          snap: false,  // false, or xy or [x,y] or function(x,y){ return [x,y] }
          delay: 0
        };
        
        if(!arguments[1] || Object.isUndefined(arguments[1].endeffect))
          Object.extend(defaults, {
            starteffect: function(element) {
              element._opacity = Element.getOpacity(element);
              Draggable._dragging[element] = true;
              new Effect.Opacity(element, {duration:0.2, from:element._opacity, to:0.7}); 
            }
          });
        
        var options = Object.extend(defaults, arguments[1] || { });
    
        this.element = $(element);
        
        if(options.handle && Object.isString(options.handle))
          this.handle = this.element.down('.'+options.handle, 0);
        
        if(!this.handle) this.handle = $(options.handle);
        if(!this.handle) this.handle = this.element;
        
        if(options.scroll && !options.scroll.scrollTo && !options.scroll.outerHTML) {
          options.scroll = $(options.scroll);
          this._isScrollChild = Element.childOf(this.element, options.scroll);
        }
    
        Element.makePositioned(this.element); // fix IE    
    
        this.options  = options;
        this.dragging = false;   
    
        this.eventMouseDown = this.initDrag.bindAsEventListener(this);
        Event.observe(this.handle, "mousedown", this.eventMouseDown);
        
        Draggables.register(this);
      },
      
      destroy: function() {
        Event.stopObserving(this.handle, "mousedown", this.eventMouseDown);
        Draggables.unregister(this);
      },
      
      currentDelta: function() {
        return([
          parseInt(Element.getStyle(this.element,'left') || '0'),
          parseInt(Element.getStyle(this.element,'top') || '0')]);
      },
      
      initDrag: function(event) {
        if(!Object.isUndefined(Draggable._dragging[this.element]) &&
          Draggable._dragging[this.element]) return;
        if(Event.isLeftClick(event)) {    
          // abort on form elements, fixes a Firefox issue
          var src = Event.element(event);
          if((tag_name = src.tagName.toUpperCase()) && (
            tag_name=='INPUT' ||
            tag_name=='SELECT' ||
            tag_name=='OPTION' ||
            tag_name=='BUTTON' ||
            tag_name=='TEXTAREA')) return;
            
          var pointer = [Event.pointerX(event), Event.pointerY(event)];
          var pos     = Position.cumulativeOffset(this.element);
          this.offset = [0,1].map( function(i) { return (pointer[i] - pos[i]) });
          
          Draggables.activate(this);
          Event.stop(event);
        }
      },
      
      startDrag: function(event) {
        this.dragging = true;
        if(!this.delta)
          this.delta = this.currentDelta();
        
        if(this.options.zindex) {
          this.originalZ = parseInt(Element.getStyle(this.element,'z-index') || 0);
          this.element.style.zIndex = this.options.zindex;
        }
        
        if(this.options.ghosting) {
          this._clone = this.element.cloneNode(true);
          this.element._originallyAbsolute = (this.element.getStyle('position') == 'absolute');
          if (!this.element._originallyAbsolute)
            Position.absolutize(this.element);
          this.element.parentNode.insertBefore(this._clone, this.element);
        }
        
        if(this.options.scroll) {
          if (this.options.scroll == window) {
            var where = this._getWindowScroll(this.options.scroll);
            this.originalScrollLeft = where.left;
            this.originalScrollTop = where.top;
          } else {
            this.originalScrollLeft = this.options.scroll.scrollLeft;
            this.originalScrollTop = this.options.scroll.scrollTop;
          }
        }
        
        Draggables.notify('onStart', this, event);
            
        if(this.options.starteffect) this.options.starteffect(this.element);
      },
      
      updateDrag: function(event, pointer) {
        if(!this.dragging) this.startDrag(event);
        
        if(!this.options.quiet){
          Position.prepare();
          Droppables.show(pointer, this.element);
        }
        
        Draggables.notify('onDrag', this, event);
        
        this.draw(pointer);
        if(this.options.change) this.options.change(this);
        
        if(this.options.scroll) {
          this.stopScrolling();
          
          var p;
          if (this.options.scroll == window) {
            with(this._getWindowScroll(this.options.scroll)) { p = [ left, top, left+width, top+height ]; }
          } else {
            p = Position.page(this.options.scroll);
            p[0] += this.options.scroll.scrollLeft + Position.deltaX;
            p[1] += this.options.scroll.scrollTop + Position.deltaY;
            p.push(p[0]+this.options.scroll.offsetWidth);
            p.push(p[1]+this.options.scroll.offsetHeight);
          }
          var speed = [0,0];
          if(pointer[0] < (p[0]+this.options.scrollSensitivity)) speed[0] = pointer[0]-(p[0]+this.options.scrollSensitivity);
          if(pointer[1] < (p[1]+this.options.scrollSensitivity)) speed[1] = pointer[1]-(p[1]+this.options.scrollSensitivity);
          if(pointer[0] > (p[2]-this.options.scrollSensitivity)) speed[0] = pointer[0]-(p[2]-this.options.scrollSensitivity);
          if(pointer[1] > (p[3]-this.options.scrollSensitivity)) speed[1] = pointer[1]-(p[3]-this.options.scrollSensitivity);
          this.startScrolling(speed);
        }
        
        // fix AppleWebKit rendering
        if(Prototype.Browser.WebKit) window.scrollBy(0,0);
        
        Event.stop(event);
      },
      
      finishDrag: function(event, success) {
        this.dragging = false;
        
        if(this.options.quiet){
          Position.prepare();
          var pointer = [Event.pointerX(event), Event.pointerY(event)];
          Droppables.show(pointer, this.element);
        }
    
        if(this.options.ghosting) {
          if (!this.element._originallyAbsolute)
            Position.relativize(this.element);
          delete this.element._originallyAbsolute;
          Element.remove(this._clone);
          this._clone = null;
        }
    
        var dropped = false; 
        if(success) { 
          dropped = Droppables.fire(event, this.element); 
          if (!dropped) dropped = false; 
        }
        if(dropped && this.options.onDropped) this.options.onDropped(this.element);
        Draggables.notify('onEnd', this, event);
    
        var revert = this.options.revert;
        if(revert && Object.isFunction(revert)) revert = revert(this.element);
        
        var d = this.currentDelta();
        if(revert && this.options.reverteffect) {
          if (dropped == 0 || revert != 'failure')
            this.options.reverteffect(this.element,
              d[1]-this.delta[1], d[0]-this.delta[0]);
        } else {
          this.delta = d;
        }
    
        if(this.options.zindex)
          this.element.style.zIndex = this.originalZ;
    
        if(this.options.endeffect) 
          this.options.endeffect(this.element);
          
        Draggables.deactivate(this);
        Droppables.reset();
      },
      
      keyPress: function(event) {
        if(event.keyCode!=Event.KEY_ESC) return;
        this.finishDrag(event, false);
        Event.stop(event);
      },
      
      endDrag: function(event) {
        if(!this.dragging) return;
        this.stopScrolling();
        this.finishDrag(event, true);
        Event.stop(event);
      },
      
      draw: function(point) {
        var pos = Position.cumulativeOffset(this.element);
        if(this.options.ghosting) {
          var r   = Position.realOffset(this.element);
          pos[0] += r[0] - Position.deltaX; pos[1] += r[1] - Position.deltaY;
        }
        
        var d = this.currentDelta();
        pos[0] -= d[0]; pos[1] -= d[1];
        
        if(this.options.scroll && (this.options.scroll != window && this._isScrollChild)) {
          pos[0] -= this.options.scroll.scrollLeft-this.originalScrollLeft;
          pos[1] -= this.options.scroll.scrollTop-this.originalScrollTop;
        }
        
        var p = [0,1].map(function(i){ 
          return (point[i]-pos[i]-this.offset[i]) 
        }.bind(this));
        
        if(this.options.snap) {
          if(Object.isFunction(this.options.snap)) {
            p = this.options.snap(p[0],p[1],this);
          } else {
          if(Object.isArray(this.options.snap)) {
            p = p.map( function(v, i) {
              return (v/this.options.snap[i]).round()*this.options.snap[i] }.bind(this))
          } else {
            p = p.map( function(v) {
              return (v/this.options.snap).round()*this.options.snap }.bind(this))
          }
        }}
        
        var style = this.element.style;
        if((!this.options.constraint) || (this.options.constraint=='horizontal'))
          style.left = p[0] + "px";
        if((!this.options.constraint) || (this.options.constraint=='vertical'))
          style.top  = p[1] + "px";
        
        if(style.visibility=="hidden") style.visibility = ""; // fix gecko rendering
      },
      
      stopScrolling: function() {
        if(this.scrollInterval) {
          clearInterval(this.scrollInterval);
          this.scrollInterval = null;
          Draggables._lastScrollPointer = null;
        }
      },
      
      startScrolling: function(speed) {
        if(!(speed[0] || speed[1])) return;
        this.scrollSpeed = [speed[0]*this.options.scrollSpeed,speed[1]*this.options.scrollSpeed];
        this.lastScrolled = new Date();
        this.scrollInterval = setInterval(this.scroll.bind(this), 10);
      },
      
      scroll: function() {
        var current = new Date();
        var delta = current - this.lastScrolled;
        this.lastScrolled = current;
        if(this.options.scroll == window) {
          with (this._getWindowScroll(this.options.scroll)) {
            if (this.scrollSpeed[0] || this.scrollSpeed[1]) {
              var d = delta / 1000;
              this.options.scroll.scrollTo( left + d*this.scrollSpeed[0], top + d*this.scrollSpeed[1] );
            }
          }
        } else {
          this.options.scroll.scrollLeft += this.scrollSpeed[0] * delta / 1000;
          this.options.scroll.scrollTop  += this.scrollSpeed[1] * delta / 1000;
        }
        
        Position.prepare();
        Droppables.show(Draggables._lastPointer, this.element);
        Draggables.notify('onDrag', this);
        if (this._isScrollChild) {
          Draggables._lastScrollPointer = Draggables._lastScrollPointer || $A(Draggables._lastPointer);
          Draggables._lastScrollPointer[0] += this.scrollSpeed[0] * delta / 1000;
          Draggables._lastScrollPointer[1] += this.scrollSpeed[1] * delta / 1000;
          if (Draggables._lastScrollPointer[0] < 0)
            Draggables._lastScrollPointer[0] = 0;
          if (Draggables._lastScrollPointer[1] < 0)
            Draggables._lastScrollPointer[1] = 0;
          this.draw(Draggables._lastScrollPointer);
        }
        
        if(this.options.change) this.options.change(this);
      },
      
      _getWindowScroll: function(w) {
        var T, L, W, H;
        with (w.document) {
          if (w.document.documentElement && documentElement.scrollTop) {
            T = documentElement.scrollTop;
            L = documentElement.scrollLeft;
          } else if (w.document.body) {
            T = body.scrollTop;
            L = body.scrollLeft;
          }
          if (w.innerWidth) {
            W = w.innerWidth;
            H = w.innerHeight;
          } else if (w.document.documentElement && documentElement.clientWidth) {
            W = documentElement.clientWidth;
            H = documentElement.clientHeight;
          } else {
            W = body.offsetWidth;
            H = body.offsetHeight
          }
        }
        return { top: T, left: L, width: W, height: H };
      }
    });
    
    Draggable._dragging = { };
    
    /*--------------------------------------------------------------------------*/
    
    var SortableObserver = Class.create({
      initialize: function(element, observer) {
        this.element   = $(element);
        this.observer  = observer;
        this.lastValue = Sortable.serialize(this.element);
      },
      
      onStart: function() {
        this.lastValue = Sortable.serialize(this.element);
      },
      
      onEnd: function() {
        Sortable.unmark();
        if(this.lastValue != Sortable.serialize(this.element))
          this.observer(this.element)
      }
    });
    
    var Sortable = {
      SERIALIZE_RULE: /^[^_\-](?:[A-Za-z0-9\-\_]*)[_](.*)$/,
      
      sortables: { },
      
      _findRootElement: function(element) {
        while (element.tagName.toUpperCase() != "BODY") {  
          if(element.id && Sortable.sortables[element.id]) return element;
          element = element.parentNode;
        }
      },
    
      options: function(element) {
        element = Sortable._findRootElement($(element));
        if(!element) return;
        return Sortable.sortables[element.id];
      },
      
      destroy: function(element){
        var s = Sortable.options(element);
        
        if(s) {
          Draggables.removeObserver(s.element);
          s.droppables.each(function(d){ Droppables.remove(d) });
          s.draggables.invoke('destroy');
          
          delete Sortable.sortables[s.element.id];
        }
      },
    
      create: function(element) {
        element = $(element);
        var options = Object.extend({ 
          element:     element,
          tag:         'li',       // assumes li children, override with tag: 'tagname'
          dropOnEmpty: false,
          tree:        false,
          treeTag:     'ul',
          overlap:     'vertical', // one of 'vertical', 'horizontal'
          constraint:  'vertical', // one of 'vertical', 'horizontal', false
          containment: element,    // also takes array of elements (or id's); or false
          handle:      false,      // or a CSS class
          only:        false,
          delay:       0,
          hoverclass:  null,
          ghosting:    false,
          quiet:       false, 
          scroll:      false,
          scrollSensitivity: 20,
          scrollSpeed: 15,
          format:      this.SERIALIZE_RULE,
          
          // these take arrays of elements or ids and can be 
          // used for better initialization performance
          elements:    false,
          handles:     false,
          
          onChange:    Prototype.emptyFunction,
          onUpdate:    Prototype.emptyFunction
        }, arguments[1] || { });
    
        // clear any old sortable with same element
        this.destroy(element);
    
        // build options for the draggables
        var options_for_draggable = {
          revert:      true,
          quiet:       options.quiet,
          scroll:      options.scroll,
          scrollSpeed: options.scrollSpeed,
          scrollSensitivity: options.scrollSensitivity,
          delay:       options.delay,
          ghosting:    options.ghosting,
          constraint:  options.constraint,
          handle:      options.handle };
    
        if(options.starteffect)
          options_for_draggable.starteffect = options.starteffect;
    
        if(options.reverteffect)
          options_for_draggable.reverteffect = options.reverteffect;
        else
          if(options.ghosting) options_for_draggable.reverteffect = function(element) {
            element.style.top  = 0;
            element.style.left = 0;
          };
    
        if(options.endeffect)
          options_for_draggable.endeffect = options.endeffect;
    
        if(options.zindex)
          options_for_draggable.zindex = options.zindex;
    
        // build options for the droppables  
        var options_for_droppable = {
          overlap:     options.overlap,
          containment: options.containment,
          tree:        options.tree,
          hoverclass:  options.hoverclass,
          onHover:     Sortable.onHover
        }
        
        var options_for_tree = {
          onHover:      Sortable.onEmptyHover,
          overlap:      options.overlap,
          containment:  options.containment,
          hoverclass:   options.hoverclass
        }
    
        // fix for gecko engine
        Element.cleanWhitespace(element); 
    
        options.draggables = [];
        options.droppables = [];
    
        // drop on empty handling
        if(options.dropOnEmpty || options.tree) {
          Droppables.add(element, options_for_tree);
          options.droppables.push(element);
        }
    
        (options.elements || this.findElements(element, options) || []).each( function(e,i) {
          var handle = options.handles ? $(options.handles[i]) :
            (options.handle ? $(e).select('.' + options.handle)[0] : e); 
          options.draggables.push(
            new Draggable(e, Object.extend(options_for_draggable, { handle: handle })));
          Droppables.add(e, options_for_droppable);
          if(options.tree) e.treeNode = element;
          options.droppables.push(e);      
        });
        
        if(options.tree) {
          (Sortable.findTreeElements(element, options) || []).each( function(e) {
            Droppables.add(e, options_for_tree);
            e.treeNode = element;
            options.droppables.push(e);
          });
        }
    
        // keep reference
        this.sortables[element.id] = options;
    
        // for onupdate
        Draggables.addObserver(new SortableObserver(element, options.onUpdate));
    
      },
    
      // return all suitable-for-sortable elements in a guaranteed order
      findElements: function(element, options) {
        return Element.findChildren(
          element, options.only, options.tree ? true : false, options.tag);
      },
      
      findTreeElements: function(element, options) {
        return Element.findChildren(
          element, options.only, options.tree ? true : false, options.treeTag);
      },
    
      onHover: function(element, dropon, overlap) {
        if(Element.isParent(dropon, element)) return;
    
        if(overlap > .33 && overlap < .66 && Sortable.options(dropon).tree) {
          return;
        } else if(overlap>0.5) {
          Sortable.mark(dropon, 'before');
          if(dropon.previousSibling != element) {
            var oldParentNode = element.parentNode;
            element.style.visibility = "hidden"; // fix gecko rendering
            dropon.parentNode.insertBefore(element, dropon);
            if(dropon.parentNode!=oldParentNode) 
              Sortable.options(oldParentNode).onChange(element);
            Sortable.options(dropon.parentNode).onChange(element);
          }
        } else {
          Sortable.mark(dropon, 'after');
          var nextElement = dropon.nextSibling || null;
          if(nextElement != element) {
            var oldParentNode = element.parentNode;
            element.style.visibility = "hidden"; // fix gecko rendering
            dropon.parentNode.insertBefore(element, nextElement);
            if(dropon.parentNode!=oldParentNode) 
              Sortable.options(oldParentNode).onChange(element);
            Sortable.options(dropon.parentNode).onChange(element);
          }
        }
      },
      
      onEmptyHover: function(element, dropon, overlap) {
        var oldParentNode = element.parentNode;
        var droponOptions = Sortable.options(dropon);
            
        if(!Element.isParent(dropon, element)) {
          var index;
          
          var children = Sortable.findElements(dropon, {tag: droponOptions.tag, only: droponOptions.only});
          var child = null;
                
          if(children) {
            var offset = Element.offsetSize(dropon, droponOptions.overlap) * (1.0 - overlap);
            
            for (index = 0; index < children.length; index += 1) {
              if (offset - Element.offsetSize (children[index], droponOptions.overlap) >= 0) {
                offset -= Element.offsetSize (children[index], droponOptions.overlap);
              } else if (offset - (Element.offsetSize (children[index], droponOptions.overlap) / 2) >= 0) {
                child = index + 1 < children.length ? children[index + 1] : null;
                break;
              } else {
                child = children[index];
                break;
              }
            }
          }
          
          dropon.insertBefore(element, child);
          
          Sortable.options(oldParentNode).onChange(element);
          droponOptions.onChange(element);
        }
      },
    
      unmark: function() {
        if(Sortable._marker) Sortable._marker.hide();
      },
    
      mark: function(dropon, position) {
        // mark on ghosting only
        var sortable = Sortable.options(dropon.parentNode);
        if(sortable && !sortable.ghosting) return; 
    
        if(!Sortable._marker) {
          Sortable._marker = 
            ($('dropmarker') || Element.extend(document.createElement('DIV'))).
              hide().addClassName('dropmarker').setStyle({position:'absolute'});
          document.getElementsByTagName("body").item(0).appendChild(Sortable._marker);
        }    
        var offsets = Position.cumulativeOffset(dropon);
        Sortable._marker.setStyle({left: offsets[0]+'px', top: offsets[1] + 'px'});
        
        if(position=='after')
          if(sortable.overlap == 'horizontal') 
            Sortable._marker.setStyle({left: (offsets[0]+dropon.clientWidth) + 'px'});
          else
            Sortable._marker.setStyle({top: (offsets[1]+dropon.clientHeight) + 'px'});
        
        Sortable._marker.show();
      },
      
      _tree: function(element, options, parent) {
        var children = Sortable.findElements(element, options) || [];
      
        for (var i = 0; i < children.length; ++i) {
          var match = children[i].id.match(options.format);
    
          if (!match) continue;
          
          var child = {
            id: encodeURIComponent(match ? match[1] : null),
            element: element,
            parent: parent,
            children: [],
            position: parent.children.length,
            container: $(children[i]).down(options.treeTag)
          }
          
          /* Get the element containing the children and recurse over it */
          if (child.container)
            this._tree(child.container, options, child)
          
          parent.children.push (child);
        }
    
        return parent; 
      },
    
      tree: function(element) {
        element = $(element);
        var sortableOptions = this.options(element);
        var options = Object.extend({
          tag: sortableOptions.tag,
          treeTag: sortableOptions.treeTag,
          only: sortableOptions.only,
          name: element.id,
          format: sortableOptions.format
        }, arguments[1] || { });
        
        var root = {
          id: null,
          parent: null,
          children: [],
          container: element,
          position: 0
        }
        
        return Sortable._tree(element, options, root);
      },
    
      /* Construct a [i] index for a particular node */
      _constructIndex: function(node) {
        var index = '';
        do {
          if (node.id) index = '[' + node.position + ']' + index;
        } while ((node = node.parent) != null);
        return index;
      },
    
      sequence: function(element) {
        element = $(element);
        var options = Object.extend(this.options(element), arguments[1] || { });
        
        return $(this.findElements(element, options) || []).map( function(item) {
          return item.id.match(options.format) ? item.id.match(options.format)[1] : '';
        });
      },
    
      setSequence: function(element, new_sequence) {
        element = $(element);
        var options = Object.extend(this.options(element), arguments[2] || { });
        
        var nodeMap = { };
        this.findElements(element, options).each( function(n) {
            if (n.id.match(options.format))
                nodeMap[n.id.match(options.format)[1]] = [n, n.parentNode];
            n.parentNode.removeChild(n);
        });
       
        new_sequence.each(function(ident) {
          var n = nodeMap[ident];
          if (n) {
            n[1].appendChild(n[0]);
            delete nodeMap[ident];
          }
        });
      },
      
      serialize: function(element) {
        element = $(element);
        var options = Object.extend(Sortable.options(element), arguments[1] || { });
        var name = encodeURIComponent(
          (arguments[1] && arguments[1].name) ? arguments[1].name : element.id);
        
        if (options.tree) {
          return Sortable.tree(element, arguments[1]).children.map( function (item) {
            return [name + Sortable._constructIndex(item) + "[id]=" + 
                    encodeURIComponent(item.id)].concat(item.children.map(arguments.callee));
          }).flatten().join('&');
        } else {
          return Sortable.sequence(element, arguments[1]).map( function(item) {
            return name + "[]=" + encodeURIComponent(item);
          }).join('&');
        }
      }
    }
    
    // Returns true if child is contained within element
    Element.isParent = function(child, element) {
      if (!child.parentNode || child == element) return false;
      if (child.parentNode == element) return true;
      return Element.isParent(child.parentNode, element);
    }
    
    Element.findChildren = function(element, only, recursive, tagName) {   
      if(!element.hasChildNodes()) return null;
      tagName = tagName.toUpperCase();
      if(only) only = [only].flatten();
      var elements = [];
      $A(element.childNodes).each( function(e) {
        if(e.tagName && e.tagName.toUpperCase()==tagName &&
          (!only || (Element.classNames(e).detect(function(v) { return only.include(v) }))))
            elements.push(e);
        if(recursive) {
          var grandchildren = Element.findChildren(e, only, recursive, tagName);
          if(grandchildren) elements.push(grandchildren);
        }
      });
    
      return (elements.length>0 ? elements.flatten() : []);
    }
    
    Element.offsetSize = function (element, type) {
      return element['offset' + ((type=='vertical' || type=='height') ? 'Height' : 'Width')];
    }