dragdrop.js

这是一款js组建

    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 };
  }
}

/*--------------------------------------------------------------------------*/

var SortableObserver = Class.create();
SortableObserver.prototype = {
  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,
      scroll:      false,
      scrollSensitivity: 20,
      scrollSpeed: 15,
      format:      this.SERIALIZE_RULE,
      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,
      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);
    }

    (this.findElements(element, options) || []).each( function(e) {
      // handles are per-draggable
      var handle = options.handle ? 
        $(e).down('.'+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')];
}