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author | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
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committer | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
commit | 33058f2b292b3a581333bdfb21b8f671898c5060 (patch) | |
tree | 51c3e392513ec574331b2d3f85c394445ea803c6 /files/zh-cn/web/api/datatransfer/cleardata/index.html | |
parent | 8b66d724f7caf0157093fb09cfec8fbd0c6ad50a (diff) | |
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diff --git a/files/zh-cn/web/api/datatransfer/cleardata/index.html b/files/zh-cn/web/api/datatransfer/cleardata/index.html new file mode 100644 index 0000000000..66f518db63 --- /dev/null +++ b/files/zh-cn/web/api/datatransfer/cleardata/index.html @@ -0,0 +1,237 @@ +--- +title: DataTransfer.clearData() +slug: Web/API/DataTransfer/clearData +tags: + - DataTransfer.clearData() +translation_of: Web/API/DataTransfer/clearData +--- +<div>{{APIRef("HTML Drag and Drop API")}}</div> + +<p><strong><code>DataTransfer.clearData()</code></strong> 方法删除给定类型的拖动操作的{{domxref("DataTransfer","drag data")}}。如果给定类型的数据不存在,则此方法不执行任何操作。</p> + +<p class="note">如果没有参数调用此方法,或者格式为空 ,则将删除所有类型的数据。</p> + +<p>此方法不会从拖动操作中删除文件,因此如果有任何文件包含在对象的{{domxref("DataTransfer.types")}}列表中,仍然可能有一个类型为“Files”的条目在拖动。 </p> + +<div class="note"> +<p>该方法只能在{{event("dragstart")}} 事件的处理程序中使用,因为这是拖动操作的数据存储只能写入的时间。</p> +</div> + +<h2 id="句法">句法</h2> + +<pre class="syntaxbox"><var>DataTransfer</var>.clearData([<em>format</em>]); +</pre> + +<h3 id="参数">参数</h3> + +<dl> + <dt><code>format</code> {{optional_inline}}</dt> + <dd>一个 {{domxref("DOMString","string")}}指定要删除的数据类型。如果此参数为空字符串或未提供,则将删除所有类型的数据。</dd> +</dl> + +<h2 id="范例">范例</h2> + +<p>这个例子显示了使用{{domxref("DataTransfer")}}对象的{{domxref("DataTransfer.getData()","getData()")}}, {{domxref("DataTransfer.setData()","setData()")}} 和{{domxref("DataTransfer.clearData()","clearData()")}} 和</p> + +<h3 id="HTML">HTML</h3> + +<pre class="brush: html"><span class="tweaked" id="source" draggable="true"> + Select this element, drag it to the Drop Zone and then release the selection to move the element. +</span> +<span class="tweaked" id="target">Drop Zone</span> +<div>Status: <span id="status">Drag to start</span></div> +<div>Data is: <span id="data">uninitialized</span></div> +</pre> + +<h3 id="CSS">CSS</h3> + +<pre class="brush: css">span.tweaked { + display: inline-block; + margin: 1em 0; + padding: 1em 2em; +} + +#source { + color: blue; + border: 1px solid black; +} + +#target { + border: 1px solid black; +} +</pre> + +<h3 id="JavaScript">JavaScript</h3> + +<pre class="brush: js">window.addEventListener('DOMContentLoaded', function () { + // Select HTML elements + var draggable = document.getElementById('source'); + var dropable = document.getElementById('target'); + var status = document.getElementById('status'); + var data = document.getElementById('data'); + var dropped = false; + + // Register event handlers + draggable.addEventListener('dragstart', dragStartHandler); + draggable.addEventListener('dragend', dragEndHandler); + dropable.addEventListener('dragover', dragOverHandler); + dropable.addEventListener('dragleave', dragLeaveHandler); + dropable.addEventListener('drop', dropHandler); + + function dragStartHandler (event) { + status.innerHTML = 'Drag in process'; + + // Change target element's border to signify drag has started + event.currentTarget.style.border = '1px dashed blue'; + + // Start by clearing existing clipboards; this will affect all types since we + // don't give a specific type. + + event.dataTransfer.clearData(); + + // Set the drag's format and data (use event target's id for data) + event.dataTransfer.setData('text/plain', event.target.id); + + data.innerHTML = event.dataTransfer.getData('text/plain'); + } + + function dragEndHandler (event) { + if (!dropped) { + status.innerHTML = 'Drag canceled'; + } + + data.innerHTML = event.dataTransfer.getData('text/plain') || 'empty'; + + // Change border to signify drag is no longer in process + event.currentTarget.style.border = '1px solid black'; + + if (dropped) { + // Remove all event listeners + draggable.removeEventListener('dragstart', dragStartHandler); + draggable.removeEventListener('dragend', dragEndHandler); + dropable.removeEventListener('dragover', dragOverHandler); + dropable.removeEventListener('dragleave', dragLeaveHandler); + dropable.removeEventListener('drop', dropHandler); + } + } + + function dragOverHandler (event) { + status.innerHTML = 'Drop available'; + + event.preventDefault(); + } + + function dragLeaveHandler (event) { + status.innerHTML = 'Drag in process (drop was available)'; + + event.preventDefault(); + } + + function dropHandler (event) { + dropped = true; + + status.innerHTML = 'Drop done'; + + event.preventDefault(); + + // Get data linked to event format « text » + var _data = event.dataTransfer.getData('text/plain'); + var element = document.getElementById(_data); + + // Append drag source element to event's target element + event.target.appendChild(element); + + // Change CSS styles and displayed text + element.style.cssText = 'border: 1px solid black;display: block; color: red'; + element.innerHTML = "I'm in the Drop Zone!"; + } +}) +</pre> + +<p>{{EmbedLiveSample('Example', 300, 250)}}</p> + +<h2 id="规范">规范</h2> + +<table class="standard-table"> + <tbody> + <tr> + <th scope="col">Specification</th> + <th scope="col">Status</th> + <th scope="col">Comment</th> + </tr> + <tr> + <td>{{SpecName('HTML WHATWG', 'interaction.html#dom-datatransfer-cleardata','DataTransfer.clearData()')}}</td> + <td>{{Spec2('HTML WHATWG')}}</td> + <td> </td> + </tr> + <tr> + <td>{{SpecName('HTML5.1', 'editing.html#dom-datatransfer-cleardata','DataTransfer.clearData()')}}</td> + <td>{{Spec2('HTML5.1')}}</td> + <td>Initial definition</td> + </tr> + </tbody> +</table> + +<h2 id="浏览器兼容性">浏览器兼容性</h2> + +<p>{{CompatibilityTable}}</p> + +<div id="compat-desktop"> +<table class="compat-table"> + <tbody> + <tr> + <th>Feature</th> + <th>Chrome</th> + <th>Edge</th> + <th>Firefox (Gecko)</th> + <th>Internet Explorer</th> + <th>Opera</th> + <th>Safari (WebKit)</th> + </tr> + <tr> + <td>Basic support</td> + <td>4</td> + <td>{{CompatVersionUnknown}}</td> + <td>{{CompatGeckoDesktop("1.9.1")}}</td> + <td>10</td> + <td>12</td> + <td>3.1</td> + </tr> + </tbody> +</table> +</div> + +<div id="compat-mobile"> +<table class="compat-table"> + <tbody> + <tr> + <th>Feature</th> + <th>Android</th> + <th>Android Webview</th> + <th>Chrome for Android</th> + <th>Edge</th> + <th>Firefox Mobile (Gecko)</th> + <th>Firefox OS</th> + <th>IE Mobile</th> + <th>Opera Mobile</th> + <th>Safari Mobile</th> + </tr> + <tr> + <td>Basic support</td> + <td>{{CompatNo}}</td> + <td>{{CompatNo}}</td> + <td>{{CompatNo}}</td> + <td>{{CompatVersionUnknown}}</td> + <td>{{CompatNo}}</td> + <td>{{CompatNo}}</td> + <td>{{CompatIE("10")}}</td> + <td>{{CompatNo}}</td> + <td>{{CompatNo}}</td> + </tr> + </tbody> +</table> +</div> + +<h2 id="也可以看看">也可以看看</h2> + +<p>{{page("/en-US/docs/Web/API/DataTransfer", "See also")}}</p> |