[Sommaire] [Imprimer]

   1  // script.aculo.us dragdrop.js v1.6.4, Wed Sep 06 11:30:58 CEST 2006
   2  
   3  // Copyright (c) 2005 Thomas Fuchs (http://script.aculo.us, http://mir.aculo.us)
   4  //           (c) 2005 Sammi Williams (http://www.oriontransfer.co.nz, sammi@oriontransfer.co.nz)
   5  // 
   6  // See scriptaculous.js for full license.
   7  
   8  /*--------------------------------------------------------------------------*/
   9  
  10  if(typeof Effect == 'undefined')
  11    throw("dragdrop.js requires including script.aculo.us' effects.js library");
  12  
  13  var Droppables = {
  14    drops: [],
  15  
  16    remove: function(element) {
  17      this.drops = this.drops.reject(function(d) { return d.element==$(element) });
  18    },
  19  
  20    add: function(element) {
  21      element = $(element);
  22      var options = Object.extend({
  23        greedy:     true,
  24        hoverclass: null,
  25        tree:       false
  26      }, arguments[1] || {});
  27  
  28      // cache containers
  29      if(options.containment) {
  30        options._containers = [];
  31        var containment = options.containment;
  32        if((typeof containment == 'object') && 
  33          (containment.constructor == Array)) {
  34          containment.each( function(c) { options._containers.push($(c)) });
  35        } else {
  36          options._containers.push($(containment));
  37        }
  38      }
  39      
  40      if(options.accept) options.accept = [options.accept].flatten();
  41  
  42      Element.makePositioned(element); // fix IE
  43      options.element = element;
  44  
  45      this.drops.push(options);
  46    },
  47    
  48    findDeepestChild: function(drops) {
  49      deepest = drops[0];
  50        
  51      for (i = 1; i < drops.length; ++i)
  52        if (Element.isParent(drops[i].element, deepest.element))
  53          deepest = drops[i];
  54      
  55      return deepest;
  56    },
  57  
  58    isContained: function(element, drop) {
  59      var containmentNode;
  60      if(drop.tree) {
  61        containmentNode = element.treeNode; 
  62      } else {
  63        containmentNode = element.parentNode;
  64      }
  65      return drop._containers.detect(function(c) { return containmentNode == c });
  66    },
  67    
  68    isAffected: function(point, element, drop) {
  69      return (
  70        (drop.element!=element) &&
  71        ((!drop._containers) ||
  72          this.isContained(element, drop)) &&
  73        ((!drop.accept) ||
  74          (Element.classNames(element).detect( 
  75            function(v) { return drop.accept.include(v) } ) )) &&
  76        Position.within(drop.element, point[0], point[1]) );
  77    },
  78  
  79    deactivate: function(drop) {
  80      if(drop.hoverclass)
  81        Element.removeClassName(drop.element, drop.hoverclass);
  82      this.last_active = null;
  83    },
  84  
  85    activate: function(drop) {
  86      if(drop.hoverclass)
  87        Element.addClassName(drop.element, drop.hoverclass);
  88      this.last_active = drop;
  89    },
  90  
  91    show: function(point, element) {
  92      if(!this.drops.length) return;
  93      var affected = [];
  94      
  95      if(this.last_active) this.deactivate(this.last_active);
  96      this.drops.each( function(drop) {
  97        if(Droppables.isAffected(point, element, drop))
  98          affected.push(drop);
  99      });
 100          
 101      if(affected.length>0) {
 102        drop = Droppables.findDeepestChild(affected);
 103        Position.within(drop.element, point[0], point[1]);
 104        if(drop.onHover)
 105          drop.onHover(element, drop.element, Position.overlap(drop.overlap, drop.element));
 106        
 107        Droppables.activate(drop);
 108      }
 109    },
 110  
 111    fire: function(event, element) {
 112      if(!this.last_active) return;
 113      Position.prepare();
 114  
 115      if (this.isAffected([Event.pointerX(event), Event.pointerY(event)], element, this.last_active))
 116        if (this.last_active.onDrop) 
 117          this.last_active.onDrop(element, this.last_active.element, event);
 118    },
 119  
 120    reset: function() {
 121      if(this.last_active)
 122        this.deactivate(this.last_active);
 123    }
 124  }
 125  
 126  var Draggables = {
 127    drags: [],
 128    observers: [],
 129    
 130    register: function(draggable) {
 131      if(this.drags.length == 0) {
 132        this.eventMouseUp   = this.endDrag.bindAsEventListener(this);
 133        this.eventMouseMove = this.updateDrag.bindAsEventListener(this);
 134        this.eventKeypress  = this.keyPress.bindAsEventListener(this);
 135        
 136        Event.observe(document, "mouseup", this.eventMouseUp);
 137        Event.observe(document, "mousemove", this.eventMouseMove);
 138        Event.observe(document, "keypress", this.eventKeypress);
 139      }
 140      this.drags.push(draggable);
 141    },
 142    
 143    unregister: function(draggable) {
 144      this.drags = this.drags.reject(function(d) { return d==draggable });
 145      if(this.drags.length == 0) {
 146        Event.stopObserving(document, "mouseup", this.eventMouseUp);
 147        Event.stopObserving(document, "mousemove", this.eventMouseMove);
 148        Event.stopObserving(document, "keypress", this.eventKeypress);
 149      }
 150    },
 151    
 152    activate: function(draggable) {
 153      if(draggable.options.delay) { 
 154        this._timeout = setTimeout(function() { 
 155          Draggables._timeout = null; 
 156          window.focus(); 
 157          Draggables.activeDraggable = draggable; 
 158        }.bind(this), draggable.options.delay); 
 159      } else {
 160        window.focus(); // allows keypress events if window isn't currently focused, fails for Safari
 161        this.activeDraggable = draggable;
 162      }
 163    },
 164    
 165    deactivate: function() {
 166      this.activeDraggable = null;
 167    },
 168    
 169    updateDrag: function(event) {
 170      if(!this.activeDraggable) return;
 171      var pointer = [Event.pointerX(event), Event.pointerY(event)];
 172      // Mozilla-based browsers fire successive mousemove events with
 173      // the same coordinates, prevent needless redrawing (moz bug?)
 174      if(this._lastPointer && (this._lastPointer.inspect() == pointer.inspect())) return;
 175      this._lastPointer = pointer;
 176      
 177      this.activeDraggable.updateDrag(event, pointer);
 178    },
 179    
 180    endDrag: function(event) {
 181      if(this._timeout) { 
 182        clearTimeout(this._timeout); 
 183        this._timeout = null; 
 184      }
 185      if(!this.activeDraggable) return;
 186      this._lastPointer = null;
 187      this.activeDraggable.endDrag(event);
 188      this.activeDraggable = null;
 189    },
 190    
 191    keyPress: function(event) {
 192      if(this.activeDraggable)
 193        this.activeDraggable.keyPress(event);
 194    },
 195    
 196    addObserver: function(observer) {
 197      this.observers.push(observer);
 198      this._cacheObserverCallbacks();
 199    },
 200    
 201    removeObserver: function(element) {  // element instead of observer fixes mem leaks
 202      this.observers = this.observers.reject( function(o) { return o.element==element });
 203      this._cacheObserverCallbacks();
 204    },
 205    
 206    notify: function(eventName, draggable, event) {  // 'onStart', 'onEnd', 'onDrag'
 207      if(this[eventName+'Count'] > 0)
 208        this.observers.each( function(o) {
 209          if(o[eventName]) o[eventName](eventName, draggable, event);
 210        });
 211      if(draggable.options[eventName]) draggable.options[eventName](draggable, event);
 212    },
 213    
 214    _cacheObserverCallbacks: function() {
 215      ['onStart','onEnd','onDrag'].each( function(eventName) {
 216        Draggables[eventName+'Count'] = Draggables.observers.select(
 217          function(o) { return o[eventName]; }
 218        ).length;
 219      });
 220    }
 221  }
 222  
 223  /*--------------------------------------------------------------------------*/
 224  
 225  var Draggable = Class.create();
 226  Draggable._dragging    = {};
 227  
 228  Draggable.prototype = {
 229    initialize: function(element) {
 230      var defaults = {
 231        handle: false,
 232        reverteffect: function(element, top_offset, left_offset) {
 233          var dur = Math.sqrt(Math.abs(top_offset^2)+Math.abs(left_offset^2))*0.02;
 234          new Effect.Move(element, { x: -left_offset, y: -top_offset, duration: dur,
 235            queue: {scope:'_draggable', position:'end'}
 236          });
 237        },
 238        endeffect: function(element) {
 239          var toOpacity = typeof element._opacity == 'number' ? element._opacity : 1.0;
 240          new Effect.Opacity(element, {duration:0.2, from:0.7, to:toOpacity, 
 241            queue: {scope:'_draggable', position:'end'},
 242            afterFinish: function(){ 
 243              Draggable._dragging[element] = false 
 244            }
 245          }); 
 246        },
 247        zindex: 1000,
 248        revert: false,
 249        scroll: false,
 250        scrollSensitivity: 20,
 251        scrollSpeed: 15,
 252        snap: false,  // false, or xy or [x,y] or function(x,y){ return [x,y] }
 253        delay: 0
 254      };
 255      
 256      if(arguments[1] && typeof arguments[1].endeffect == 'undefined')
 257        Object.extend(defaults, {
 258          starteffect: function(element) {
 259            element._opacity = Element.getOpacity(element);
 260            Draggable._dragging[element] = true;
 261            new Effect.Opacity(element, {duration:0.2, from:element._opacity, to:0.7}); 
 262          }
 263        });
 264      
 265      var options = Object.extend(defaults, arguments[1] || {});
 266  
 267      this.element = $(element);
 268      
 269      if(options.handle && (typeof options.handle == 'string')) {
 270        var h = Element.childrenWithClassName(this.element, options.handle, true);
 271        if(h.length>0) this.handle = h[0];
 272      }
 273      if(!this.handle) this.handle = $(options.handle);
 274      if(!this.handle) this.handle = this.element;
 275      
 276      if(options.scroll && !options.scroll.scrollTo && !options.scroll.outerHTML) {
 277        options.scroll = $(options.scroll);
 278        this._isScrollChild = Element.childOf(this.element, options.scroll);
 279      }
 280  
 281      Element.makePositioned(this.element); // fix IE    
 282  
 283      this.delta    = this.currentDelta();
 284      this.options  = options;
 285      this.dragging = false;   
 286  
 287      this.eventMouseDown = this.initDrag.bindAsEventListener(this);
 288      Event.observe(this.handle, "mousedown", this.eventMouseDown);
 289      
 290      Draggables.register(this);
 291    },
 292    
 293    destroy: function() {
 294      Event.stopObserving(this.handle, "mousedown", this.eventMouseDown);
 295      Draggables.unregister(this);
 296    },
 297    
 298    currentDelta: function() {
 299      return([
 300        parseInt(Element.getStyle(this.element,'left') || '0'),
 301        parseInt(Element.getStyle(this.element,'top') || '0')]);
 302    },
 303    
 304    initDrag: function(event) {
 305      if(typeof Draggable._dragging[this.element] != 'undefined' &&
 306        Draggable._dragging[this.element]) return;
 307      if(Event.isLeftClick(event)) {    
 308        // abort on form elements, fixes a Firefox issue
 309        var src = Event.element(event);
 310        if(src.tagName && (
 311          src.tagName=='INPUT' ||
 312          src.tagName=='SELECT' ||
 313          src.tagName=='OPTION' ||
 314          src.tagName=='BUTTON' ||
 315          src.tagName=='TEXTAREA')) return;
 316          
 317        var pointer = [Event.pointerX(event), Event.pointerY(event)];
 318        var pos     = Position.cumulativeOffset(this.element);
 319        this.offset = [0,1].map( function(i) { return (pointer[i] - pos[i]) });
 320        
 321        Draggables.activate(this);
 322        Event.stop(event);
 323      }
 324    },
 325    
 326    startDrag: function(event) {
 327      this.dragging = true;
 328      
 329      if(this.options.zindex) {
 330        this.originalZ = parseInt(Element.getStyle(this.element,'z-index') || 0);
 331        this.element.style.zIndex = this.options.zindex;
 332      }
 333      
 334      if(this.options.ghosting) {
 335        this._clone = this.element.cloneNode(true);
 336        Position.absolutize(this.element);
 337        this.element.parentNode.insertBefore(this._clone, this.element);
 338      }
 339      
 340      if(this.options.scroll) {
 341        if (this.options.scroll == window) {
 342          var where = this._getWindowScroll(this.options.scroll);
 343          this.originalScrollLeft = where.left;
 344          this.originalScrollTop = where.top;
 345        } else {
 346          this.originalScrollLeft = this.options.scroll.scrollLeft;
 347          this.originalScrollTop = this.options.scroll.scrollTop;
 348        }
 349      }
 350      
 351      Draggables.notify('onStart', this, event);
 352          
 353      if(this.options.starteffect) this.options.starteffect(this.element);
 354    },
 355    
 356    updateDrag: function(event, pointer) {
 357      if(!this.dragging) this.startDrag(event);
 358      Position.prepare();
 359      Droppables.show(pointer, this.element);
 360      Draggables.notify('onDrag', this, event);
 361      
 362      this.draw(pointer);
 363      if(this.options.change) this.options.change(this);
 364      
 365      if(this.options.scroll) {
 366        this.stopScrolling();
 367        
 368        var p;
 369        if (this.options.scroll == window) {
 370          with(this._getWindowScroll(this.options.scroll)) { p = [ left, top, left+width, top+height ]; }
 371        } else {
 372          p = Position.page(this.options.scroll);
 373          p[0] += this.options.scroll.scrollLeft;
 374          p[1] += this.options.scroll.scrollTop;
 375          
 376          p[0] += (window.pageXOffset || document.documentElement.scrollLeft || document.body.scrollLeft || 0);
 377          p[1] += (window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop || 0);
 378          
 379          p.push(p[0]+this.options.scroll.offsetWidth);
 380          p.push(p[1]+this.options.scroll.offsetHeight);
 381        }
 382        var speed = [0,0];
 383        if(pointer[0] < (p[0]+this.options.scrollSensitivity)) speed[0] = pointer[0]-(p[0]+this.options.scrollSensitivity);
 384        if(pointer[1] < (p[1]+this.options.scrollSensitivity)) speed[1] = pointer[1]-(p[1]+this.options.scrollSensitivity);
 385        if(pointer[0] > (p[2]-this.options.scrollSensitivity)) speed[0] = pointer[0]-(p[2]-this.options.scrollSensitivity);
 386        if(pointer[1] > (p[3]-this.options.scrollSensitivity)) speed[1] = pointer[1]-(p[3]-this.options.scrollSensitivity);
 387        this.startScrolling(speed);
 388      }
 389      
 390      // fix AppleWebKit rendering
 391      if(navigator.appVersion.indexOf('AppleWebKit')>0) window.scrollBy(0,0);
 392      
 393      Event.stop(event);
 394    },
 395    
 396    finishDrag: function(event, success) {
 397      this.dragging = false;
 398  
 399      if(this.options.ghosting) {
 400        Position.relativize(this.element);
 401        Element.remove(this._clone);
 402        this._clone = null;
 403      }
 404  
 405      if(success) Droppables.fire(event, this.element);
 406      Draggables.notify('onEnd', this, event);
 407  
 408      var revert = this.options.revert;
 409      if(revert && typeof revert == 'function') revert = revert(this.element);
 410      
 411      var d = this.currentDelta();
 412      if(revert && this.options.reverteffect) {
 413        this.options.reverteffect(this.element, 
 414          d[1]-this.delta[1], d[0]-this.delta[0]);
 415      } else {
 416        this.delta = d;
 417      }
 418  
 419      if(this.options.zindex)
 420        this.element.style.zIndex = this.originalZ;
 421  
 422      if(this.options.endeffect) 
 423        this.options.endeffect(this.element);
 424        
 425      Draggables.deactivate(this);
 426      Droppables.reset();
 427    },
 428    
 429    keyPress: function(event) {
 430      if(event.keyCode!=Event.KEY_ESC) return;
 431      this.finishDrag(event, false);
 432      Event.stop(event);
 433    },
 434    
 435    endDrag: function(event) {
 436      if(!this.dragging) return;
 437      this.stopScrolling();
 438      this.finishDrag(event, true);
 439      Event.stop(event);
 440    },
 441    
 442    draw: function(point) {
 443      var pos = Position.cumulativeOffset(this.element);
 444      if(this.options.ghosting) {
 445        var r   = Position.realOffset(this.element);
 446        window.status = r.inspect();
 447        pos[0] += r[0] - Position.deltaX; pos[1] += r[1] - Position.deltaY;
 448      }
 449      
 450      var d = this.currentDelta();
 451      pos[0] -= d[0]; pos[1] -= d[1];
 452      
 453      if(this.options.scroll && (this.options.scroll != window && this._isScrollChild)) {
 454        pos[0] -= this.options.scroll.scrollLeft-this.originalScrollLeft;
 455        pos[1] -= this.options.scroll.scrollTop-this.originalScrollTop;
 456      }
 457      
 458      var p = [0,1].map(function(i){ 
 459        return (point[i]-pos[i]-this.offset[i]) 
 460      }.bind(this));
 461      
 462      if(this.options.snap) {
 463        if(typeof this.options.snap == 'function') {
 464          p = this.options.snap(p[0],p[1],this);
 465        } else {
 466        if(this.options.snap instanceof Array) {
 467          p = p.map( function(v, i) {
 468            return Math.round(v/this.options.snap[i])*this.options.snap[i] }.bind(this))
 469        } else {
 470          p = p.map( function(v) {
 471            return Math.round(v/this.options.snap)*this.options.snap }.bind(this))
 472        }
 473      }}
 474      
 475      var style = this.element.style;
 476      if((!this.options.constraint) || (this.options.constraint=='horizontal'))
 477        style.left = p[0] + "px";
 478      if((!this.options.constraint) || (this.options.constraint=='vertical'))
 479        style.top  = p[1] + "px";
 480      
 481      if(style.visibility=="hidden") style.visibility = ""; // fix gecko rendering
 482    },
 483    
 484    stopScrolling: function() {
 485      if(this.scrollInterval) {
 486        clearInterval(this.scrollInterval);
 487        this.scrollInterval = null;
 488        Draggables._lastScrollPointer = null;
 489      }
 490    },
 491    
 492    startScrolling: function(speed) {
 493      if(!(speed[0] || speed[1])) return;
 494      this.scrollSpeed = [speed[0]*this.options.scrollSpeed,speed[1]*this.options.scrollSpeed];
 495      this.lastScrolled = new Date();
 496      this.scrollInterval = setInterval(this.scroll.bind(this), 10);
 497    },
 498    
 499    scroll: function() {
 500      var current = new Date();
 501      var delta = current - this.lastScrolled;
 502      this.lastScrolled = current;
 503      if(this.options.scroll == window) {
 504        with (this._getWindowScroll(this.options.scroll)) {
 505          if (this.scrollSpeed[0] || this.scrollSpeed[1]) {
 506            var d = delta / 1000;
 507            this.options.scroll.scrollTo( left + d*this.scrollSpeed[0], top + d*this.scrollSpeed[1] );
 508          }
 509        }
 510      } else {
 511        this.options.scroll.scrollLeft += this.scrollSpeed[0] * delta / 1000;
 512        this.options.scroll.scrollTop  += this.scrollSpeed[1] * delta / 1000;
 513      }
 514      
 515      Position.prepare();
 516      Droppables.show(Draggables._lastPointer, this.element);
 517      Draggables.notify('onDrag', this);
 518      if (this._isScrollChild) {
 519        Draggables._lastScrollPointer = Draggables._lastScrollPointer || $A(Draggables._lastPointer);
 520        Draggables._lastScrollPointer[0] += this.scrollSpeed[0] * delta / 1000;
 521        Draggables._lastScrollPointer[1] += this.scrollSpeed[1] * delta / 1000;
 522        if (Draggables._lastScrollPointer[0] < 0)
 523          Draggables._lastScrollPointer[0] = 0;
 524        if (Draggables._lastScrollPointer[1] < 0)
 525          Draggables._lastScrollPointer[1] = 0;
 526        this.draw(Draggables._lastScrollPointer);
 527      }
 528      
 529      if(this.options.change) this.options.change(this);
 530    },
 531    
 532    _getWindowScroll: function(w) {
 533      var T, L, W, H;
 534      with (w.document) {
 535        if (w.document.documentElement && documentElement.scrollTop) {
 536          T = documentElement.scrollTop;
 537          L = documentElement.scrollLeft;
 538        } else if (w.document.body) {
 539          T = body.scrollTop;
 540          L = body.scrollLeft;
 541        }
 542        if (w.innerWidth) {
 543          W = w.innerWidth;
 544          H = w.innerHeight;
 545        } else if (w.document.documentElement && documentElement.clientWidth) {
 546          W = documentElement.clientWidth;
 547          H = documentElement.clientHeight;
 548        } else {
 549          W = body.offsetWidth;
 550          H = body.offsetHeight
 551        }
 552      }
 553      return { top: T, left: L, width: W, height: H };
 554    }
 555  }
 556  
 557  /*--------------------------------------------------------------------------*/
 558  
 559  var SortableObserver = Class.create();
 560  SortableObserver.prototype = {
 561    initialize: function(element, observer) {
 562      this.element   = $(element);
 563      this.observer  = observer;
 564      this.lastValue = Sortable.serialize(this.element);
 565    },
 566    
 567    onStart: function() {
 568      this.lastValue = Sortable.serialize(this.element);
 569    },
 570    
 571    onEnd: function() {
 572      Sortable.unmark();
 573      if(this.lastValue != Sortable.serialize(this.element))
 574        this.observer(this.element)
 575    }
 576  }
 577  
 578  var Sortable = {
 579    SERIALIZE_RULE: /^[^_\-](?:[A-Za-z0-9\-\_]*)[_](.*)$/,
 580    
 581    sortables: {},
 582    
 583    _findRootElement: function(element) {
 584      while (element.tagName != "BODY") {  
 585        if(element.id && Sortable.sortables[element.id]) return element;
 586        element = element.parentNode;
 587      }
 588    },
 589  
 590    options: function(element) {
 591      element = Sortable._findRootElement($(element));
 592      if(!element) return;
 593      return Sortable.sortables[element.id];
 594    },
 595    
 596    destroy: function(element){
 597      var s = Sortable.options(element);
 598      
 599      if(s) {
 600        Draggables.removeObserver(s.element);
 601        s.droppables.each(function(d){ Droppables.remove(d) });
 602        s.draggables.invoke('destroy');
 603        
 604        delete Sortable.sortables[s.element.id];
 605      }
 606    },
 607  
 608    create: function(element) {
 609      element = $(element);
 610      var options = Object.extend({ 
 611        element:     element,
 612        tag:         'li',       // assumes li children, override with tag: 'tagname'
 613        dropOnEmpty: false,
 614        tree:        false,
 615        treeTag:     'ul',
 616        overlap:     'vertical', // one of 'vertical', 'horizontal'
 617        constraint:  'vertical', // one of 'vertical', 'horizontal', false
 618        containment: element,    // also takes array of elements (or id's); or false
 619        handle:      false,      // or a CSS class
 620        only:        false,
 621        delay:       0,
 622        hoverclass:  null,
 623        ghosting:    false,
 624        scroll:      false,
 625        scrollSensitivity: 20,
 626        scrollSpeed: 15,
 627        format:      this.SERIALIZE_RULE,
 628        onChange:    Prototype.emptyFunction,
 629        onUpdate:    Prototype.emptyFunction
 630      }, arguments[1] || {});
 631  
 632      // clear any old sortable with same element
 633      this.destroy(element);
 634  
 635      // build options for the draggables
 636      var options_for_draggable = {
 637        revert:      true,
 638        scroll:      options.scroll,
 639        scrollSpeed: options.scrollSpeed,
 640        scrollSensitivity: options.scrollSensitivity,
 641        delay:       options.delay,
 642        ghosting:    options.ghosting,
 643        constraint:  options.constraint,
 644        handle:      options.handle };
 645  
 646      if(options.starteffect)
 647        options_for_draggable.starteffect = options.starteffect;
 648  
 649      if(options.reverteffect)
 650        options_for_draggable.reverteffect = options.reverteffect;
 651      else
 652        if(options.ghosting) options_for_draggable.reverteffect = function(element) {
 653          element.style.top  = 0;
 654          element.style.left = 0;
 655        };
 656  
 657      if(options.endeffect)
 658        options_for_draggable.endeffect = options.endeffect;
 659  
 660      if(options.zindex)
 661        options_for_draggable.zindex = options.zindex;
 662  
 663      // build options for the droppables  
 664      var options_for_droppable = {
 665        overlap:     options.overlap,
 666        containment: options.containment,
 667        tree:        options.tree,
 668        hoverclass:  options.hoverclass,
 669        onHover:     Sortable.onHover
 670        //greedy:      !options.dropOnEmpty
 671      }
 672      
 673      var options_for_tree = {
 674        onHover:      Sortable.onEmptyHover,
 675        overlap:      options.overlap,
 676        containment:  options.containment,
 677        hoverclass:   options.hoverclass
 678      }
 679  
 680      // fix for gecko engine
 681      Element.cleanWhitespace(element); 
 682  
 683      options.draggables = [];
 684      options.droppables = [];
 685  
 686      // drop on empty handling
 687      if(options.dropOnEmpty || options.tree) {
 688        Droppables.add(element, options_for_tree);
 689        options.droppables.push(element);
 690      }
 691  
 692      (this.findElements(element, options) || []).each( function(e) {
 693        // handles are per-draggable
 694        var handle = options.handle ? 
 695          Element.childrenWithClassName(e, options.handle)[0] : e;    
 696        options.draggables.push(
 697          new Draggable(e, Object.extend(options_for_draggable, { handle: handle })));
 698        Droppables.add(e, options_for_droppable);
 699        if(options.tree) e.treeNode = element;
 700        options.droppables.push(e);      
 701      });
 702      
 703      if(options.tree) {
 704        (Sortable.findTreeElements(element, options) || []).each( function(e) {
 705          Droppables.add(e, options_for_tree);
 706          e.treeNode = element;
 707          options.droppables.push(e);
 708        });
 709      }
 710  
 711      // keep reference
 712      this.sortables[element.id] = options;
 713  
 714      // for onupdate
 715      Draggables.addObserver(new SortableObserver(element, options.onUpdate));
 716  
 717    },
 718  
 719    // return all suitable-for-sortable elements in a guaranteed order
 720    findElements: function(element, options) {
 721      return Element.findChildren(
 722        element, options.only, options.tree ? true : false, options.tag);
 723    },
 724    
 725    findTreeElements: function(element, options) {
 726      return Element.findChildren(
 727        element, options.only, options.tree ? true : false, options.treeTag);
 728    },
 729  
 730    onHover: function(element, dropon, overlap) {
 731      if(Element.isParent(dropon, element)) return;
 732  
 733      if(overlap > .33 && overlap < .66 && Sortable.options(dropon).tree) {
 734        return;
 735      } else if(overlap>0.5) {
 736        Sortable.mark(dropon, 'before');
 737        if(dropon.previousSibling != element) {
 738          var oldParentNode = element.parentNode;
 739          element.style.visibility = "hidden"; // fix gecko rendering
 740          dropon.parentNode.insertBefore(element, dropon);
 741          if(dropon.parentNode!=oldParentNode) 
 742            Sortable.options(oldParentNode).onChange(element);
 743          Sortable.options(dropon.parentNode).onChange(element);
 744        }
 745      } else {
 746        Sortable.mark(dropon, 'after');
 747        var nextElement = dropon.nextSibling || null;
 748        if(nextElement != element) {
 749          var oldParentNode = element.parentNode;
 750          element.style.visibility = "hidden"; // fix gecko rendering
 751          dropon.parentNode.insertBefore(element, nextElement);
 752          if(dropon.parentNode!=oldParentNode) 
 753            Sortable.options(oldParentNode).onChange(element);
 754          Sortable.options(dropon.parentNode).onChange(element);
 755        }
 756      }
 757    },
 758    
 759    onEmptyHover: function(element, dropon, overlap) {
 760      var oldParentNode = element.parentNode;
 761      var droponOptions = Sortable.options(dropon);
 762          
 763      if(!Element.isParent(dropon, element)) {
 764        var index;
 765        
 766        var children = Sortable.findElements(dropon, {tag: droponOptions.tag, only: droponOptions.only});
 767        var child = null;
 768              
 769        if(children) {
 770          var offset = Element.offsetSize(dropon, droponOptions.overlap) * (1.0 - overlap);
 771          
 772          for (index = 0; index < children.length; index += 1) {
 773            if (offset - Element.offsetSize (children[index], droponOptions.overlap) >= 0) {
 774              offset -= Element.offsetSize (children[index], droponOptions.overlap);
 775            } else if (offset - (Element.offsetSize (children[index], droponOptions.overlap) / 2) >= 0) {
 776              child = index + 1 < children.length ? children[index + 1] : null;
 777              break;
 778            } else {
 779              child = children[index];
 780              break;
 781            }
 782          }
 783        }
 784        
 785        dropon.insertBefore(element, child);
 786        
 787        Sortable.options(oldParentNode).onChange(element);
 788        droponOptions.onChange(element);
 789      }
 790    },
 791  
 792    unmark: function() {
 793      if(Sortable._marker) Element.hide(Sortable._marker);
 794    },
 795  
 796    mark: function(dropon, position) {
 797      // mark on ghosting only
 798      var sortable = Sortable.options(dropon.parentNode);
 799      if(sortable && !sortable.ghosting) return; 
 800  
 801      if(!Sortable._marker) {
 802        Sortable._marker = $('dropmarker') || document.createElement('DIV');
 803        Element.hide(Sortable._marker);
 804        Element.addClassName(Sortable._marker, 'dropmarker');
 805        Sortable._marker.style.position = 'absolute';
 806        document.getElementsByTagName("body").item(0).appendChild(Sortable._marker);
 807      }    
 808      var offsets = Position.cumulativeOffset(dropon);
 809      Sortable._marker.style.left = offsets[0] + 'px';
 810      Sortable._marker.style.top = offsets[1] + 'px';
 811      
 812      if(position=='after')
 813        if(sortable.overlap == 'horizontal') 
 814          Sortable._marker.style.left = (offsets[0]+dropon.clientWidth) + 'px';
 815        else
 816          Sortable._marker.style.top = (offsets[1]+dropon.clientHeight) + 'px';
 817      
 818      Element.show(Sortable._marker);
 819    },
 820    
 821    _tree: function(element, options, parent) {
 822      var children = Sortable.findElements(element, options) || [];
 823    
 824      for (var i = 0; i < children.length; ++i) {
 825        var match = children[i].id.match(options.format);
 826  
 827        if (!match) continue;
 828        
 829        var child = {
 830          id: encodeURIComponent(match ? match[1] : null),
 831          element: element,
 832          parent: parent,
 833          children: new Array,
 834          position: parent.children.length,
 835          container: Sortable._findChildrenElement(children[i], options.treeTag.toUpperCase())
 836        }
 837        
 838        /* Get the element containing the children and recurse over it */
 839        if (child.container)
 840          this._tree(child.container, options, child)
 841        
 842        parent.children.push (child);
 843      }
 844  
 845      return parent; 
 846    },
 847  
 848    /* Finds the first element of the given tag type within a parent element.
 849      Used for finding the first LI[ST] within a L[IST]I[TEM].*/
 850    _findChildrenElement: function (element, containerTag) {
 851      if (element && element.hasChildNodes)
 852        for (var i = 0; i < element.childNodes.length; ++i)
 853          if (element.childNodes[i].tagName == containerTag)
 854            return element.childNodes[i];
 855    
 856      return null;
 857    },
 858  
 859    tree: function(element) {
 860      element = $(element);
 861      var sortableOptions = this.options(element);
 862      var options = Object.extend({
 863        tag: sortableOptions.tag,
 864        treeTag: sortableOptions.treeTag,
 865        only: sortableOptions.only,
 866        name: element.id,
 867        format: sortableOptions.format
 868      }, arguments[1] || {});
 869      
 870      var root = {
 871        id: null,
 872        parent: null,
 873        children: new Array,
 874        container: element,
 875        position: 0
 876      }
 877      
 878      return Sortable._tree (element, options, root);
 879    },
 880  
 881    /* Construct a [i] index for a particular node */
 882    _constructIndex: function(node) {
 883      var index = '';
 884      do {
 885        if (node.id) index = '[' + node.position + ']' + index;
 886      } while ((node = node.parent) != null);
 887      return index;
 888    },
 889  
 890    sequence: function(element) {
 891      element = $(element);
 892      var options = Object.extend(this.options(element), arguments[1] || {});
 893      
 894      return $(this.findElements(element, options) || []).map( function(item) {
 895        return item.id.match(options.format) ? item.id.match(options.format)[1] : '';
 896      });
 897    },
 898  
 899    setSequence: function(element, new_sequence) {
 900      element = $(element);
 901      var options = Object.extend(this.options(element), arguments[2] || {});
 902      
 903      var nodeMap = {};
 904      this.findElements(element, options).each( function(n) {
 905          if (n.id.match(options.format))
 906              nodeMap[n.id.match(options.format)[1]] = [n, n.parentNode];
 907          n.parentNode.removeChild(n);
 908      });
 909     
 910      new_sequence.each(function(ident) {
 911        var n = nodeMap[ident];
 912        if (n) {
 913          n[1].appendChild(n[0]);
 914          delete nodeMap[ident];
 915        }
 916      });
 917    },
 918    
 919    serialize: function(element) {
 920      element = $(element);
 921      var options = Object.extend(Sortable.options(element), arguments[1] || {});
 922      var name = encodeURIComponent(
 923        (arguments[1] && arguments[1].name) ? arguments[1].name : element.id);
 924      
 925      if (options.tree) {
 926        return Sortable.tree(element, arguments[1]).children.map( function (item) {
 927          return [name + Sortable._constructIndex(item) + "[id]=" + 
 928                  encodeURIComponent(item.id)].concat(item.children.map(arguments.callee));
 929        }).flatten().join('&');
 930      } else {
 931        return Sortable.sequence(element, arguments[1]).map( function(item) {
 932          return name + "[]=" + encodeURIComponent(item);
 933        }).join('&');
 934      }
 935    }
 936  }
 937  
 938  /* Returns true if child is contained within element */
 939  Element.isParent = function(child, element) {
 940    if (!child.parentNode || child == element) return false;
 941  
 942    if (child.parentNode == element) return true;
 943  
 944    return Element.isParent(child.parentNode, element);
 945  }
 946  
 947  Element.findChildren = function(element, only, recursive, tagName) {    
 948    if(!element.hasChildNodes()) return null;
 949    tagName = tagName.toUpperCase();
 950    if(only) only = [only].flatten();
 951    var elements = [];
 952    $A(element.childNodes).each( function(e) {
 953      if(e.tagName && e.tagName.toUpperCase()==tagName &&
 954        (!only || (Element.classNames(e).detect(function(v) { return only.include(v) }))))
 955          elements.push(e);
 956      if(recursive) {
 957        var grandchildren = Element.findChildren(e, only, recursive, tagName);
 958        if(grandchildren) elements.push(grandchildren);
 959      }
 960    });
 961  
 962    return (elements.length>0 ? elements.flatten() : []);
 963  }
 964  
 965  Element.offsetSize = function (element, type) {
 966    if (type == 'vertical' || type == 'height')
 967      return element.offsetHeight;
 968    else
 969      return element.offsetWidth;
 970  }