PerformanceEntry.duration

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The duration property returns a timestamp that is the duration of the performance entry.

The value returned by this property depends on the performance entry's type:

  • "frame" - returns a timestamp indicating the difference between the startTimes of two successive frames.
  • "mark" - returns "0" (a mark has no duration).
  • "measure" - returns the timestamp that is the duration of the measure.
  • "navigation" - returns the timestamp that is the difference between the PerformanceEntry.loadEventEnd and PerformanceEntry.startTime properties, respectively.例如: entry.entryType "navigation",entry.duration 3611.26, entry.loadEventEnd 3611.2672285754975, entry.startTime 0;
  • "resource" - 返回 resource 的responseEnd timestamp 和  startTime timestamp的时间差. 例如: entry.entryType "resource",entry.duration 901.1400000000001, entry.responseEnd 2527.82, entry.startTime 1626.68, 2527.82 - 1626.68 == 901.1400000000001;

This property is 只读 .

Syntax

entry.duration;

Return value

A DOMHighResTimeStamp representing the duration of the performance entry. If the duration concept doesn't apply for a particular performance metric, the browser may choose to return a duration of 0.

Note: if the performance entry has an entryType of "resource" (i.e. the entry is a PerformanceResourceTiming object), this property returns the difference between the PerformanceEntry.responseEnd and PerformanceEntry.startTime timestamps.

Example

The following example shows the use of the duration property.

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");
    }
  }
}

Specifications

Specification Status Comment
Performance Timeline Level 2
duration
Candidate Recommendation  
Performance Timeline
duration
Recommendation Initial definition.

Browser compatibility

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support. (Yes) (Yes) (Yes) (Yes) (Yes) 未实现
Avaialable on workers 62 ? ? ? 49 ?
Feature Android Webview Chrome for Android Edge Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
Basic support. (Yes) (Yes) (Yes) 25.0 (25.0) 1.2 (25.0) 10.0 (Yes) 未实现
Avaialable on workers 62 62 ? ? ? ? 49 ?

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