Performance

Summary

Exposes a high precision timestamp to developers so they can better measure the performance of their applications.

Properties

No properties.

Methods

clearMarks: Removes all DOMHighResTimeStamp time values for the given mark name, or removes all marks and their associated DOMHighResTimeStamp time values.
clearMeasures: Removes all DOMHighResTimeStamp durations for the given measure name, or removes all measures and their associated DOMHighResTimeStamp durations.
mark: Stores a timestamp with the associated name (a “mark”).
measure: Stores the DOMHighResTimeStamp duration between two marks along with the associated name (a “measure”).

Events

No events.

Examples

The following script shows how a developer can use the interfaces defined in this document to obtain timing data related to developer scripts.

<!doctype html>
<html>
  <head>
    <title>User Timing example</title>
  </head>
  <body onload="init()">
    <script>
       function init()
       {
            performance.mark("startTask1");
            doTask1(); // Some developer code
            performance.mark("endTask1");

            performance.mark("startTask2");
            doTask2(); // Some developer code
            performance.mark("endTask2");

            measurePerf();
       }

       function measurePerf()
       {
           var perfEntries = performance.getEntriesByType("mark");
           for (var i = 0; i < perfEntries.length; i++)
           {
                 if (window.console) console.log("Name: "        + perfEntries[i].name      +
                                                 " Entry Type: " + perfEntries[i].entryType +
                                                 " Start Time: " + perfEntries[i].startTime +
                                                 " Duration: "   + perfEntries[i].duration  + "\n");
           }
       }
    </script>
  </body>
</html>

Related specifications

W3C User Timing Specification: W3C Candidate Recommendation

Attributions

Microsoft Developer Network: Windows Internet Explorer API reference Article