HTML5 – 一个拖拽功能的例子

我最近出席了一系列的研讨会，HTML5这个主题在这些会上反复出现。出于好奇我略看了几眼后，开始觉得应该好好的挖掘一下HTML5，看看它究竟会给我们今天技术上带来哪些好处。一个特别有意思的东西就是拖拽功能编程接口 … 早期的HTML编程开发者一直对此渴望却不可及。我感觉这个功能非常有用 … 拖拽功能的实现已经成了几个不费吹灰之力的函数调用了。
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<wbr><br> 为了演示拖拽用例，我要创建一个简单的网络配置工具(UI),管理员可以用它来收集资源。你能在各个区域之间拖拽资源，往区域里添加资源，删除没有用的资源。出于教学的目的，我尽量使这个例子简单，但可以看到，依据这些基本的做法，你可以开发出一个全功能的网络管理工具。<br><wbr></wbr></wbr>

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<wbr><br><wbr><strong><wbr>下面就是我的例子，你可以试用一下<span></span></wbr></strong><wbr>(需要Firefox 3.5 以上版本):<br></wbr></wbr></wbr>

<wbr><a href="https://www.ibm.com/developerworks/mydeveloperworks/blogs/bobleah/resource/d_and_d.html?lang=en" target="_blank" style="">https://www.ibm.com/developerworks/mydeveloperworks/blogs/bobleah/resource/d_and_d.html?lang=en</a><br><wbr><br></wbr></wbr>

<wbr><span><span></span></span><br><wbr><br><br><wbr><span><wbr>实现拖拽功能的关键方法非常的简单，就像下面写的这样：</wbr></span><wbr><br><wbr><br><wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr>function dragIt(target, e) {<br><wbr> e.da<wbr>taTr<wbr>ansf<wbr>er.s<wbr>etDa<wbr>ta(‘<wbr>Span<wbr>Img’<wbr>, target.id);<br><wbr>}<br><wbr><br><wbr>function dropIt(target, e) {<br><wbr> var id = e.da<wbr>taTr<wbr>ansf<wbr>er.g<wbr>etDa<wbr>ta(‘<wbr>Span<wbr>Img’<wbr>);<br><wbr> targ<wbr>et.a<wbr>ppen<wbr>dChi<wbr>ld(d<wbr>ocum<wbr>ent.<wbr>getE<wbr>leme<wbr>ntBy<wbr>Id(i<wbr>d));<wbr><br><wbr> e.preventDefault();<br><wbr>}<br><wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr><span style="font-weight:bold"><wbr>我使用了table元素来实现布局结构，并把它当做</wbr></span><wbr><u style="font-weight:bold"><wbr>ondrop</wbr></u><wbr><span style="font-weight:bold"><wbr>事件的目标：</wbr></span><wbr><br><wbr></wbr></wbr></wbr></wbr></wbr>

<wbr>&lt;<wbr>td align=”<wbr>center”<wbr><span></span>width=”<wbr>100″<wbr><span></span>id=”<wbr>blue”<wbr><span></span>ondrop=”<wbr>dropIt(this, event)”<wbr>ondragenter=”<wbr>return false”<wbr><span></span>ondragover=”<wbr>return false”<wbr>&gt;<wbr> …. &lt;<wbr>/td&gt;<wbr><br><wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr><span style="font-weight:bold"><wbr>我使用了span元素（包裹住图片）做</wbr></span><wbr><u style="font-weight:bold"><wbr>拖拽</wbr></u><wbr><span style="font-weight:bold"><wbr>对象：</wbr></span><wbr><br><wbr></wbr></wbr></wbr></wbr></wbr>

<wbr>&lt;<wbr>span draggable=”<wbr>true”<wbr><span></span>id=”<wbr>t_1″<wbr><span></span>ondragstart=”<wbr>dragIt(this, event)”<wbr>&gt;<wbr>&lt;<wbr>img src=”<wbr>http<wbr>s://<wbr>www.<wbr>ibm.<wbr>com/<wbr>deve<wbr>lope<wbr>rwor<wbr>ks/m<wbr>ydev<wbr>elop<wbr>erwo<wbr>rks/<wbr>blog<wbr>s/bo<wbr>blea<wbr>h/re<wbr>sour<wbr>ce/t<wbr>ower<wbr>.jpg<wbr>“<wbr>&gt;<wbr>&lt;<wbr>/span&gt;<wbr><br><wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr><br><wbr><strong><wbr>你可以下载拖拽例子中的所有的HTML代码</wbr></strong><wbr><span></span><a href="https://www.ibm.com/developerworks/mydeveloperworks/files/app?lang=en#/person/270000CN12/file/ca25c6eb-f34a-437c-85da-5b3b24b3b9bb" style="color:rgb(12,116,166); text-decoration:none"><wbr>点击下载</wbr></a><wbr>.<span></span><br><wbr><br><wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr><br><wbr>以我这初始的体验来看，HTML5将会提供给我们令人激动的用途。目前，这些API是有限制的，只在个别的浏览器里有效；对于我的例子，你需要在Firefox 3.5 版本以上才能运行。我将继续探索有哪些新功能今天我们可以使用，继续写更多的例子 … 请耐心等待！</wbr></wbr>

原文链接：

HTML5 - code example of drag and drop on a web page