diff options
Diffstat (limited to 'files/zh-cn/web/api/htmlselectelement/selectedindex/index.html')
| -rw-r--r-- | files/zh-cn/web/api/htmlselectelement/selectedindex/index.html | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/files/zh-cn/web/api/htmlselectelement/selectedindex/index.html b/files/zh-cn/web/api/htmlselectelement/selectedindex/index.html new file mode 100644 index 0000000000..90217f241b --- /dev/null +++ b/files/zh-cn/web/api/htmlselectelement/selectedindex/index.html @@ -0,0 +1,80 @@ +--- +title: HTMLSelectElement.selectedIndex +slug: Web/API/HTMLSelectElement/selectedIndex +tags: + - API + - HTML DOM + - HTMLSelectElement + - HTML表单 + - 参考 + - 属性 +translation_of: Web/API/HTMLSelectElement/selectedIndex +--- +<div>{{APIRef("HTML DOM")}}</div> + +<p><code><strong>HTMLSelectElement.selectedIndex</strong></code> 是一个长整型数，它反映了被选中的第一个 {{HTMLElement("option")}} 元素的索引值。值为-1时表明没有元素被选中。</p> + +<h2 id="语法">语法</h2> + +<pre class="syntaxbox">var <var>index</var> = <var>selectElem</var>.selectedIndex; +<em>selectElem<code>.selectedIndex = </code>index;</em> +</pre> + +<h2 id="示例">示例</h2> + +<h3 id="HTML">HTML</h3> + +<pre class="brush: html"><p id="p">selectedIndex: 0</p> + +<select id="select"> + <option selected>Option A</option> + <option>Option B</option> + <option>Option C</option> + <option>Option D</option> + <option>Option E</option> +</select> +</pre> + +<h3 id="JavaScript">JavaScript</h3> + +<pre class="brush: js; highlight[6]">var selectElem = document.getElementById('select') +var pElem = document.getElementById('p') + +// 当有新的<option>元素被选中时 +selectElem.addEventListener('change', function() { + var index = selectElem.selectedIndex; + // 把index数据添加到p元素中 + pElem.innerHTML = 'selectedIndex: ' + index; +})</pre> + +<p><iframe class="live-sample-frame sample-code-frame" frameborder="0" height="80px" id="frame_Example" src="https://mdn.mozillademos.org/en-US/docs/Web/API/HTMLSelectElement/selectedIndex$samples/Example?revision=1546597" width="200px"></iframe></p> + +<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">注释</th> + </tr> + <tr> + <td>{{SpecName('HTML WHATWG', '#dom-select-selectedindex', 'HTMLSelectElement')}}</td> + <td>{{Spec2('HTML WHATWG')}}</td> + <td>No change since the latest snapshot, {{SpecName("HTML5 W3C")}}.</td> + </tr> + <tr> + <td>{{SpecName('HTML5 W3C', 'forms.html#dom-select-selectedindex', 'HTMLSelectElement')}}</td> + <td>{{Spec2('HTML5 W3C')}}</td> + <td>Initial definition, snapshot of {{SpecName("HTML WHATWG")}}.</td> + </tr> + </tbody> +</table> + +<h2 id="浏览器兼容性">浏览器兼容性</h2> + +<p>{{Compat("api.HTMLSelectElement.selectedIndex")}}</p> + +<div></div> + +<div id="compat-mobile"></div> |