HTMLSelectElement.selectedIndex

HTMLSelectElement.selectedIndex 是一个长整型数,它反映了被选中的第一个 <option> 元素的索引值。值为-1时表明没有元素被选中。

语法

var index = selectElem.selectedIndex;
selectElem.selectedIndex = index;

示例

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>

JavaScript

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;
})

规范

规范 状态 注释
HTML Living Standard
HTMLSelectElement
Living Standard No change since the latest snapshot, HTML5.
HTML5
HTMLSelectElement
Recommendation Initial definition, snapshot of HTML Living Standard.

浏览器兼容性

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
selectedIndexChrome Full support YesEdge Full support 12Firefox Full support YesIE ? Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesFirefox Android Full support YesOpera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yes

Legend

Full support  
Full support
Compatibility unknown  
Compatibility unknown