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PerformanceEntry.toJSON()

The toJSON() method is a serializer; it returns a JSON representation of the performance entry object.

Syntax

json = perfEntry.toJSON();

Arguments

None
 

Return value

json
A JSON object that is the serialization of the PerformanceEntry object.

Example

The following example shows the use of the toJSON() method.

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 Time Level 2
The definition of 'toJSON' in that specification.
Editor's Draft Initial definition of toJSON() method.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
toJSON() (Yes) (Yes) No support No support No support
Feature Android Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
toJSON() (Yes) 25.0 (25.0) 1.2 (25.0) No support (Yes) No support

Document Tags and Contributors

 Contributors to this page: rolfedh, fscholz, AFBarstow
 Last updated by: rolfedh,