我找到了一个看起来很适合我需要的脚本，但它使用 ID 而不是类来创建 ipad 友好的拖放元素。
我真的需要它来使用类，因为可拖动元素可能有数千个。
[编辑] 我不太擅长 javascript，并且很难理解如何更改脚本以使用类而不是 ID。
我也联系了剧本作者，但没有得到他的回复。
我提供这个赏金，因为我没有对我的原始查询做出任何回应。
请有人可以更改下面的脚本以使其使用类吗？[/编辑]
下面是完整的脚本，这里是脚本页面（API 对我使用类和 id 没有帮助）。
// webkitdragdrop.js v1.0, Mon May 15 2010
//
// Copyright (c) 2010 Tommaso Buvoli (http://www.tommasobuvoli.com)
// No Extra Libraries are required, simply download this file, add it to your pages!
//
// To See this library in action, grab an ipad and head over to http://www.gotproject.com
// webkitdragdrop is freely distributable under the terms of an MIT-style license.
//Description
// Because this library was designed to run without requiring any other libraries, several basic helper functions were implemented
// 6 helper functons in this webkit_tools class have been taked directly from Prototype 1.6.1 (http://prototypejs.org/) (c) 2005-2009 Sam Stephenson
var webkit_tools =
{
//$ function - simply a more robust getElementById
$:function(e)
{
if(typeof(e) == 'string')
{
return document.getElementById(e);
}
return e;
},
//extend function - copies the values of b into a (Shallow copy)
extend:function(a,b)
{
for (var key in b)
{
a[key] = b[key];
}
return a;
},
//empty function - used as defaut for events
empty:function()
{
},
//remove null values from an array
compact:function(a)
{
var b = []
var l = a.length;
for(var i = 0; i < l; i ++)
{
if(a[i] !== null)
{
b.push(a[i]);
}
}
return b;
},
//DESCRIPTION
// This function was taken from the internet (http://robertnyman.com/2006/04/24/get-the-rendered-style-of-an-element/) and returns
// the computed style of an element independantly from the browser
//INPUT
// oELM (DOM ELEMENT) element whose style should be extracted
// strCssRule element
getCalculatedStyle:function(oElm, strCssRule)
{
var strValue = "";
if(document.defaultView && document.defaultView.getComputedStyle){
strValue = document.defaultView.getComputedStyle(oElm, "").getPropertyValue(strCssRule);
}
else if(oElm.currentStyle){
strCssRule = strCssRule.replace(/\-(\w)/g, function (strMatch, p1){
return p1.toUpperCase();
});
strValue = oElm.currentStyle[strCssRule];
}
return strValue;
},
//bindAsEventListener function - used to bind events
bindAsEventListener:function(f,object)
{
var __method = f;
return function(event) {
__method.call(object, event || window.event);
};
},
//cumulative offset - courtesy of Prototype (http://www.prototypejs.org)
cumulativeOffset:function(element)
{
var valueT = 0, valueL = 0;
do {
valueT += element.offsetTop || 0;
valueL += element.offsetLeft || 0;
if (element.offsetParent == document.body)
if (element.style.position == 'absolute') break;
element = element.offsetParent;
} while (element);
return {left : valueL, top : valueT};
},
//getDimensions - courtesy of Prototype (http://www.prototypejs.org)
getDimensions: function(element)
{
var display = element.style.display;
if (display != 'none' && display != null) // Safari bug
return {width: element.offsetWidth, height: element.offsetHeight};
var els = element.style;
var originalVisibility = els.visibility;
var originalPosition = els.position;
var originalDisplay = els.display;
els.visibility = 'hidden';
if (originalPosition != 'fixed') // Switching fixed to absolute causes issues in Safari
els.position = 'absolute';
els.display = 'block';
var originalWidth = element.clientWidth;
var originalHeight = element.clientHeight;
els.display = originalDisplay;
els.position = originalPosition;
els.visibility = originalVisibility;
return {width: originalWidth, height: originalHeight};
},
//hasClassName - courtesy of Prototype (http://www.prototypejs.org)
hasClassName: function(element, className)
{
var elementClassName = element.className;
return (elementClassName.length > 0 && (elementClassName == className ||
new RegExp("(^|\\s)" + className + "(\\s|$)").test(elementClassName)));
},
//addClassName - courtesy of Prototype (http://www.prototypejs.org)
addClassName: function(element, className)
{
if (!this.hasClassName(element, className))
element.className += (element.className ? ' ' : '') + className;
return element;
},
//removeClassName - courtesy of Prototype (http://www.prototypejs.org)
removeClassName: function(element, className)
{
element.className = this.strip(element.className.replace(new RegExp("(^|\\s+)" + className + "(\\s+|$)"), ' '));
return element;
},
//strip - courtesy of Prototype (http://www.prototypejs.org)
strip:function(s)
{
return s.replace(/^\s+/, '').replace(/\s+$/, '');
}
}
//Description
// Droppable fire events when a draggable is dropped on them
var webkit_droppables = function()
{
this.initialize = function()
{
this.droppables = [];
this.droppableRegions = [];
}
this.add = function(root, instance_props)
{
root = webkit_tools.$(root);
var default_props = {accept : [], hoverClass : null, onDrop : webkit_tools.empty, onOver : webkit_tools.empty, onOut : webkit_tools.empty};
default_props = webkit_tools.extend(default_props, instance_props || {});
this.droppables.push({r : root, p : default_props});
}
this.remove = function(root)
{
root = webkit_tools.$(root);
var d = this.droppables;
var i = d.length;
while(i--)
{
if(d[i].r == root)
{
d[i] = null;
this.droppables = webkit_tools.compact(d);
return true;
}
}
return false;
}
//calculate position and size of all droppables
this.prepare = function()
{
var d = this.droppables;
var i = d.length;
var dR = [];
var r = null;
while(i--)
{
r = d[i].r;
if(r.style.display != 'none')
{
dR.push({i : i, size : webkit_tools.getDimensions(r), offset : webkit_tools.cumulativeOffset(r)})
}
}
this.droppableRegions = dR;
}
this.finalize = function(x,y,r,e)
{
var indices = this.isOver(x,y);
var index = this.maxZIndex(indices);
var over = this.process(index,r);
if(over)
{
this.drop(index, r,e);
}
this.process(-1,r);
return over;
}
this.check = function(x,y,r)
{
var indices = this.isOver(x,y);
var index = this.maxZIndex(indices);
return this.process(index,r);
}
this.isOver = function(x, y)
{
var dR = this.droppableRegions;
var i = dR.length;
var active = [];
var r = 0;
var maxX = 0;
var minX = 0;
var maxY = 0;
var minY = 0;
while(i--)
{
r = dR[i];
minY = r.offset.top;
maxY = minY + r.size.height;
if((y > minY) && (y < maxY))
{
minX = r.offset.left;
maxX = minX + r.size.width;
if((x > minX) && (x < maxX))
{
active.push(r.i);
}
}
}
return active;
}
this.maxZIndex = function(indices)
{
var d = this.droppables;
var l = indices.length;
var index = -1;
var maxZ = -100000000;
var curZ = 0;
while(l--)
{
curZ = parseInt(d[indices[l]].r.style.zIndex || 0);
if(curZ > maxZ)
{
maxZ = curZ;
index = indices[l];
}
}
return index;
}
this.process = function(index, draggableRoot)
{
//only perform update if a change has occured
if(this.lastIndex != index)
{
//remove previous
if(this.lastIndex != null)
{
var d = this.droppables[this.lastIndex]
var p = d.p;
var r = d.r;
if(p.hoverClass)
{
webkit_tools.removeClassName(r,p.hoverClass);
}
p.onOut();
this.lastIndex = null;
this.lastOutput = false;
}
//add new
if(index != -1)
{
var d = this.droppables[index]
var p = d.p;
var r = d.r;
if(this.hasClassNames(draggableRoot, p.accept))
{
if(p.hoverClass)
{
webkit_tools.addClassName(r,p.hoverClass);
}
p.onOver();
this.lastIndex = index;
this.lastOutput = true;
}
}
}
return this.lastOutput;
}
this.drop = function(index, r, e)
{
if(index != -1)
{
this.droppables[index].p.onDrop(r,e);
}
}
this.hasClassNames = function(r, names)
{
var l = names.length;
if(l == 0){return true}
while(l--)
{
if(webkit_tools.hasClassName(r,names[l]))
{
return true;
}
}
return false;
}
this.initialize();
}
webkit_drop = new webkit_droppables();
//Description
//webkit draggable - allows users to drag elements with their hands
var webkit_draggable = function(r, ip)
{
this.initialize = function(root, instance_props)
{
this.root = webkit_tools.$(root);
var default_props = {scroll : false, revert : false, handle : this.root, zIndex : 1000, onStart : webkit_tools.empty, onEnd : webkit_tools.empty};
this.p = webkit_tools.extend(default_props, instance_props || {});
default_props.handle = webkit_tools.$(default_props.handle);
this.prepare();
this.bindEvents();
}
this.prepare = function()
{
var rs = this.root.style;
//set position
if(webkit_tools.getCalculatedStyle(this.root,'position') != 'absolute')
{
rs.position = 'relative';
}
//set top, right, bottom, left
rs.top = rs.top || '0px';
rs.left = rs.left || '0px';
rs.right = "";
rs.bottom = "";
//set zindex;
rs.zIndex = rs.zIndex || '0';
}
this.bindEvents = function()
{
var handle = this.p.handle;
this.ts = webkit_tools.bindAsEventListener(this.touchStart, this);
this.tm = webkit_tools.bindAsEventListener(this.touchMove, this);
this.te = webkit_tools.bindAsEventListener(this.touchEnd, this);
handle.addEventListener("touchstart", this.ts, false);
handle.addEventListener("touchmove", this.tm, false);
handle.addEventListener("touchend", this.te, false);
}
this.destroy = function()
{
var handle = this.p.handle;
handle.removeEventListener("touchstart", this.ts);
handle.removeEventListener("touchmove", this.tm);
handle.removeEventListener("touchend", this.te);
}
this.set = function(key, value)
{
this.p[key] = value;
}
this.touchStart = function(event)
{
//prepare needed variables
var p = this.p;
var r = this.root;
var rs = r.style;
var t = event.targetTouches[0];
//get position of touch
touchX = t.pageX;
touchY = t.pageY;
//set base values for position of root
rs.top = this.root.style.top || '0px';
rs.left = this.root.style.left || '0px';
rs.bottom = null;
rs.right = null;
var rootP = webkit_tools.cumulativeOffset(r);
var cp = this.getPosition();
//save event properties
p.rx = cp.x;
p.ry = cp.y;
p.tx = touchX;
p.ty = touchY;
p.z = parseInt(this.root.style.zIndex);
//boost zIndex
rs.zIndex = p.zIndex;
webkit_drop.prepare();
p.onStart();
}
this.touchMove = function(event)
{
event.preventDefault();
event.stopPropagation();
//prepare needed variables
var p = this.p;
var r = this.root;
var rs = r.style;
var t = event.targetTouches[0];
if(t == null){return}
var curX = t.pageX;
var curY = t.pageY;
var delX = curX - p.tx;
var delY = curY - p.ty;
rs.left = p.rx + delX + 'px';
rs.top = p.ry + delY + 'px';
//scroll window
if(p.scroll)
{
s = this.getScroll(curX, curY);
if((s[0] != 0) || (s[1] != 0))
{
window.scrollTo(window.scrollX + s[0], window.scrollY + s[1]);
}
}
//check droppables
webkit_drop.check(curX, curY, r);
//save position for touchEnd
this.lastCurX = curX;
this.lastCurY = curY;
}
this.touchEnd = function(event)
{
var r = this.root;
var p = this.p;
var dropped = webkit_drop.finalize(this.lastCurX, this.lastCurY, r, event);
if(((p.revert) && (!dropped)) || (p.revert === 'always'))
{
//revert root
var rs = r.style;
rs.top = (p.ry + 'px');
rs.left = (p.rx + 'px');
}
r.style.zIndex = this.p.z;
this.p.onEnd();
}
this.getPosition = function()
{
var rs = this.root.style;
return {x : parseInt(rs.left || 0), y : parseInt(rs.top || 0)}
}
this.getScroll = function(pX, pY)
{
//read window variables
var sX = window.scrollX;
var sY = window.scrollY;
var wX = window.innerWidth;
var wY = window.innerHeight;
//set contants
var scroll_amount = 10; //how many pixels to scroll
var scroll_sensitivity = 100; //how many pixels from border to start scrolling from.
var delX = 0;
var delY = 0;
//process vertical y scroll
if(pY - sY < scroll_sensitivity)
{
delY = -scroll_amount;
}
else
if((sY + wY) - pY < scroll_sensitivity)
{
delY = scroll_amount;
}
//process horizontal x scroll
if(pX - sX < scroll_sensitivity)
{
delX = -scroll_amount;
}
else
if((sX + wX) - pX < scroll_sensitivity)
{
delX = scroll_amount;
}
return [delX, delY]
}
//contructor
this.initialize(r, ip);
}
//Description
//webkit_click class. manages click events for draggables
var webkit_click = function(r, ip)
{
this.initialize = function(root, instance_props)
{
var default_props = {onClick : webkit_tools.empty};
this.root = webkit_tools.$(root);
this.p = webkit_tools.extend(default_props, instance_props || {});
this.bindEvents();
}
this.bindEvents = function()
{
var root = this.root;
//bind events to local scope
this.ts = webkit_tools.bindAsEventListener(this.touchStart,this);
this.tm = webkit_tools.bindAsEventListener(this.touchMove,this);
this.te = webkit_tools.bindAsEventListener(this.touchEnd,this);
//add Listeners
root.addEventListener("touchstart", this.ts, false);
root.addEventListener("touchmove", this.tm, false);
root.addEventListener("touchend", this.te, false);
this.bound = true;
}
this.touchStart = function()
{
this.moved = false;
if(this.bound == false)
{
this.root.addEventListener("touchmove", this.tm, false);
this.bound = true;
}
}
this.touchMove = function()
{
this.moved = true;
this.root.removeEventListener("touchmove", this.tm);
this.bound = false;
}
this.touchEnd = function()
{
if(this.moved == false)
{
this.p.onClick();
}
}
this.setEvent = function(f)
{
if(typeof(f) == 'function')
{
this.p.onClick = f;
}
}
this.unbind = function()
{
var root = this.root;
root.removeEventListener("touchstart", this.ts);
root.removeEventListener("touchmove", this.tm);
root.removeEventListener("touchend", this.te);
}
//call constructor
this.initialize(r, ip);
}