opac/public/javascripts/dragdrop.js

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