在此页

• 特性
• 方法
• 范例
• 规范
• 浏览器兼容性
• 相关话题

LayoutShift interface of the Layout Instability API provides insights into the stability of web pages based on movements of the elements on the page.

特性

LayoutShift.value

返回 impact fraction (fraction of the viewport that was shifted) times the distance fraction (distance moved as a fraction of viewport).

LayoutShift.hadRecentInput

返回 true if there was a user input in the past 500 milliseconds.

LayoutShift.lastInputTime

Returns the time of the most recent user input.

LayoutShift.sources

Returns an array of LayoutShiftAttribution objects with information on the elements that were shifted.

方法

LayoutShift.toJSON()

Converts the properties to JSON.

范例

The following example shows how to capture layout shifts and log them to the console.

Note that in this example data is only sent to the server when the user leaves the tab.

// Catch errors since some browsers throw when using the new `type` option.
// https://bugs.webkit.org/show_bug.cgi?id=209216
try {
  let cumulativeLayoutShiftScore = 0;
  const observer = new PerformanceObserver((list) => {
  for (const entry of list.getEntries()) {
    // Only count layout shifts without recent user input.
    if (!entry.hadRecentInput) {
      cumulativeLayoutShiftScore += entry.value;
    }
  }
  });
  observer.observe({type: 'layout-shift', buffered: true});
  document.addEventListener('visibilitychange', () => {
  if (document.visibilityState === 'hidden') {
    // Force any pending records to be dispatched.
    observer.takeRecords();
    observer.disconnect();
    console.log('CLS:', cumulativeLayoutShiftScore);
  }
  });
} catch (e) {
  // Do nothing if the browser doesn't support this API.
}
					

规范

规范	状态	注释
Layout Instability API The definition of 'LayoutShift' in that specification.	编者草案	初始定义。

浏览器兼容性

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
LayoutShift	Chrome 77	Edge 80	Firefox No	IE No	Opera Yes	Safari No	WebView Android 77	Chrome Android 77	Firefox Android No	Opera Android Yes	Safari iOS No	Samsung Internet Android 12.0
hadRecentInput	Chrome 77	Edge 80	Firefox No	IE No	Opera Yes	Safari No	WebView Android 77	Chrome Android 77	Firefox Android No	Opera Android Yes	Safari iOS No	Samsung Internet Android 12.0
lastInputTime	Chrome 77	Edge 80	Firefox No	IE No	Opera Yes	Safari No	WebView Android 77	Chrome Android 77	Firefox Android No	Opera Android Yes	Safari iOS No	Samsung Internet Android 12.0
toJSON	Chrome 77	Edge 80	Firefox No	IE No	Opera Yes	Safari No	WebView Android 77	Chrome Android 77	Firefox Android No	Opera Android Yes	Safari iOS No	Samsung Internet Android 12.0
value	Chrome 77	Edge 80	Firefox No	IE No	Opera Yes	Safari No	WebView Android 77	Chrome Android 77	Firefox Android No	Opera Android Yes	Safari iOS No	Samsung Internet Android 12.0

图例

完整支持

完整支持

不支持

不支持

实验。期望将来行为有所改变。

实验。期望将来行为有所改变。

元数据

• 最后修改： May 15, 2020