在此页

• 句法
• 范例
• 规范
• 浏览器兼容性
• 相关话题

toJSON() method is a serializer ; it returns a JSON representation of the performance entry 对象。

注意： 此特征可用于 Web 工作者 .

句法

json = perfEntry.toJSON();
					

自变量

None

返回值

json

A JSON object that is the serialization of the PerformanceEntry 对象。

范例

The following example shows the use of the toJSON() 方法。

function run_PerformanceEntry() {
  log("PerformanceEntry support ...");
  if (performance.mark === undefined) {
    log("... performance.mark Not supported");
    return;
  }
  // Create some performance entries via the mark() method
  performance.mark("Begin");
  do_work(50000);
  performance.mark("End");
  // Use getEntries() to iterate through the each entry
  var p = performance.getEntries();
  for (var i=0; i < p.length; i++) {
    log("Entry[" + i + "]");
    check_PerformanceEntry(p[i]);
  }
}
function check_PerformanceEntry(obj) {
  var properties = ["name", "entryType", "startTime", "duration"];
  var methods = ["toJSON"];
  for (var i=0; i < properties.length; i++) {
    // check each property
    var supported = properties[i] in obj;
    if (supported)
      log("..." + properties[i] + " = " + obj[properties[i]]);
    else
      log("..." + properties[i] + " = Not supported");
  }
  for (var i=0; i < methods.length; i++) {
    // check each method
    var supported = typeof obj[methods[i]] == "function";
    if (supported) {
      var js = obj[methods[i]]();
      log("..." + methods[i] + "() = " + JSON.stringify(js));
    } else {
      log("..." + methods[i] + " = Not supported");
    }
  }
}
					

规范

规范	状态	注释
Performance Timeline Level 2 The definition of 'toJSON' in that specification.	候选推荐	Initial definition of toJSON() 方法。

浏览器兼容性

The compatibility table on 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
toJSON	Chrome Yes	Edge 16	Firefox Yes	IE 不支持 No	Opera Yes	Safari 11	WebView Android Yes	Chrome Android Yes	Firefox Android 25	Opera Android Yes	Safari iOS 11	Samsung Internet Android Yes

图例

完整支持

完整支持

不支持

不支持

元数据

• 最后修改： 2019 年 3 月 23 日

相关话题

1. 性能时间线
2. PerformanceEntry
3. 特性

   1. duration
   2. entryType
   3. 名称
   4. startTime
4. 方法

   1. toJSON()
5. Related pages for Performance Timeline API

   1. 性能
   2. PerformanceObserver
   3. PerformanceObserverEntryList
   4. PerformanceResourceTiming
   5. Window.performance