PerformanceObserver()
Baseline Widely available *
This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.
* Some parts of this feature may have varying levels of support.
PerformanceObserver() 构造函数使用给定的观察者 callback 生成一个新的 PerformanceObserver 对象。当通过 observe() 方法注册的 条目类型 的 性能条目事件 被记录下来时，调用该观察者回调。
语法
js
var observer = new PerformanceObserver(callback);
参数
返回值
一个在观察的性能事件发生时调用指定的 callback 的新 PerformanceObserver 对象。
例子
js
var observer = new PerformanceObserver(function (list, obj) {
var entries = list.getEntries();
for (var i = 0; i < entries.length; i++) {
// Process "mark" and "frame" events
}
});
observer.observe({ entryTypes: ["mark", "frame"] });
function perf_observer(list, observer) {
// Process the "measure" event
}
var observer2 = new PerformanceObserver(perf_observer);
observer2.observe({ entryTypes: ["measure"] });
规范
| Specification |
|---|
| Performance Timeline # dom-performanceobserver-constructor |