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 |