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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/idbcursor/key | |
parent | 8b66d724f7caf0157093fb09cfec8fbd0c6ad50a (diff) | |
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Diffstat (limited to 'files/zh-cn/web/api/idbcursor/key')
-rw-r--r-- | files/zh-cn/web/api/idbcursor/key/index.html | 194 |
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diff --git a/files/zh-cn/web/api/idbcursor/key/index.html b/files/zh-cn/web/api/idbcursor/key/index.html new file mode 100644 index 0000000000..573890a7fa --- /dev/null +++ b/files/zh-cn/web/api/idbcursor/key/index.html @@ -0,0 +1,194 @@ +--- +title: IDBCursor.key +slug: Web/API/IDBCursor/key +translation_of: Web/API/IDBCursor/key +--- +<p>{{APIRef("IndexedDB")}}</p> + +<div> +<p><strong>key</strong>是只读属性,返回在游标中的位置。如果游标在范围之外,这个值会被置为undefined。游标的key可以是任何数据类型。</p> + +<p>{{AvailableInWorkers}}</p> +</div> + +<h2 id="语法">语法</h2> + +<pre class="syntaxbox" style="font-size: 14px;">var <em>key = cursor</em>.key;</pre> + +<h3 id="值">值</h3> + +<p>任意类型</p> + +<h2 id="示例">示例</h2> + +<p>在该示例中,我们创建一个事务,检索一个存储对象,然后使用游标遍历所有存储在object store 中的记录。遍历的过程中,我们把类似(相簿标题,这是我们的键key),游标的key打印出来。</p> + +<p>我们可以不根据游标的key来选取数据;我们可以抓取所有。还要注意,在循环的每个迭代中,您可以使用cursor.value.foo从当前记录下获取数据。完整示例,请看<span style="line-height: 1.5;"><a href="https://github.com/mdn/IDBcursor-example/">IDBCursor example</a></span><span style="line-height: 1.5;"> (</span><a href="http://mdn.github.io/IDBcursor-example/" style="line-height: 1.5;">view example live</a><span style="line-height: 1.5;">.)</span></p> + +<pre style="font-size: 14px;"><span style="line-height: 1.5;">function displayData() {</span> + var transaction = db.transaction(['rushAlbumList'], "readonly"); + var objectStore = transaction.objectStore('rushAlbumList'); + + objectStore.openCursor().onsuccess = function(event) { + var cursor = event.target.result; + if(cursor) { + var listItem = document.createElement('li'); + listItem.innerHTML = cursor.value.albumTitle + ', ' + cursor.value.year; + list.appendChild(listItem); + + console.log(cursor.key); + cursor.continue(); + } else { + console.log('Entries all displayed.'); + } + }; +};</pre> + +<h2 id="规范">规范</h2> + +<table class="standard-table"> + <tbody> + <tr> + <th scope="col">规范</th> + <th scope="col">状态</th> + <th scope="col">说明</th> + </tr> + <tr> + <td>{{SpecName('IndexedDB', '#widl-IDBCursor-key', 'key')}}</td> + <td>{{Spec2('IndexedDB')}}</td> + <td> </td> + </tr> + <tr> + <td>{{SpecName("IndexedDB 2", "#dom-idbcursor-key", "key")}}</td> + <td>{{Spec2("IndexedDB 2")}}</td> + <td> </td> + </tr> + </tbody> +</table> + +<h2 id="Browser_compatibility" name="Browser_compatibility">浏览器兼容性</h2> + +<div>{{CompatibilityTable}}</div> + +<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>23{{property_prefix("webkit")}}<br> + 24</td> + <td>{{CompatVersionUnknown}}</td> + <td>10 {{property_prefix("moz")}}<br> + {{CompatGeckoDesktop("16.0")}}</td> + <td>10, partial</td> + <td>15</td> + <td>7.1</td> + </tr> + <tr> + <td>Available in workers</td> + <td>{{CompatVersionUnknown}}</td> + <td>{{CompatVersionUnknown}}</td> + <td>{{CompatGeckoDesktop("37.0")}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatVersionUnknown}}</td> + <td>{{CompatUnknown}}</td> + </tr> + <tr> + <td>Binary keys</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatGeckoDesktop("51.0")}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatUnknown}}</td> + </tr> + <tr> + <td>Indexed Database 2.0</td> + <td>{{CompatChrome(58)}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatOpera(45)}}</td> + <td>{{CompatUnknown}}</td> + </tr> + </tbody> +</table> +</div> + +<div id="compat-mobile"> +<table class="compat-table"> + <tbody> + <tr> + <th>Feature</th> + <th>Android Webview</th> + <th>Chrome for Android</th> + <th>Edge</th> + <th>Firefox Mobile (Gecko)</th> + <th>IE Phone</th> + <th>Opera Mobile</th> + <th>Safari Mobile</th> + </tr> + <tr> + <td>Basic support</td> + <td>{{CompatVersionUnknown}}</td> + <td>{{CompatVersionUnknown}}</td> + <td>{{CompatVersionUnknown}}</td> + <td>{{CompatGeckoMobile("22.0")}}</td> + <td>10</td> + <td>22</td> + <td>8</td> + </tr> + <tr> + <td>Available in workers</td> + <td>{{CompatVersionUnknown}}</td> + <td>{{CompatVersionUnknown}}</td> + <td>{{CompatVersionUnknown}}</td> + <td>{{CompatGeckoMobile("37.0")}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatVersionUnknown}}</td> + <td>{{CompatUnknown}}</td> + </tr> + <tr> + <td>Binary keys</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatGeckoMobile("51.0")}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatUnknown}}</td> + </tr> + <tr> + <td>Indexed Database 2.0</td> + <td>{{CompatChrome(58)}}</td> + <td>{{CompatChrome(58)}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatOperaMobile(45)}}</td> + <td>{{CompatUnknown}}</td> + </tr> + </tbody> +</table> +</div> + +<h2 id="相关链接">相关链接</h2> + +<ul> + <li><a href="/en-US/docs/Web/API/IndexedDB_API/Using_IndexedDB">Using IndexedDB</a></li> + <li>Starting transactions: {{domxref("IDBDatabase")}}</li> + <li>Using transactions: {{domxref("IDBTransaction")}}</li> + <li>Setting a range of keys: {{domxref("IDBKeyRange")}}</li> + <li>Retrieving and making changes to your data: {{domxref("IDBObjectStore")}}</li> + <li>Using cursors: {{domxref("IDBCursor")}}</li> + <li>Reference example: <a class="external" href="https://github.com/mdn/to-do-notifications/tree/gh-pages">To-do Notifications</a> (<a class="external" href="http://mdn.github.io/to-do-notifications/">view example live</a>.)</li> +</ul> |