performance.measure()
The measure()
method creates a named
timestamp
in the browser's performance entry
buffer between marks, the navigation start time, or the current time. When
measuring between two marks, there is a start mark and end mark,
respectively. The named timestamp is referred to as a measure.
The measure
can be retrieved by one of the Performance
interfaces: (getEntries()
,
getEntriesByName()
or
getEntriesByType()
).
The measure
's performance entry
will
have the following property values:
entryType
- set to "measure
".name
- set to the "name
" given when the measure was created.startTime
- set to the start marktimestamp
.duration
- set to aDOMHighResTimeStamp
that is the duration of the measure (typically, the end mark timestamp minus the start mark timestamp).
Note:
This feature is available in Web Workers.Syntax
performance.measure(name);
performance.measure(name, startMark);
performance.measure(name, startMark, endMark);
performance.measure(name, undefined, endMark);
Arguments
- name
- A
DOMString
representing the name of the measure. - startMark Optional
- A
DOMString
representing the name of the measure's starting mark. May also be the name of aPerformanceTiming
property. If it is omitted, then the start time will be the navigation start time. - endMark Optional
- A
DOMString
representing the name of the measure's ending mark. May also be the name of aPerformanceTiming
property. If it is omitted, then the current time is used.
Return value
- void
Example
The following example shows how measure()
is used to create a new
measure performance entry
in the browser's
performance entry buffer.
const markerNameA = "example-marker-a"
const markerNameB = "example-marker-b"
// Run some nested timeouts, and create a PerformanceMark for each.
performance.mark(markerNameA);
setTimeout(function() {
performance.mark(markerNameB);
setTimeout(function() {
// Create a variety of measurements.
performance.measure("measure a to b", markerNameA, markerNameB);
performance.measure("measure a to now", markerNameA);
performance.measure("measure from navigation start to b", undefined, markerNameB);
performance.measure("measure from the start of navigation to now");
// Pull out all of the measurements.
console.log(performance.getEntriesByType("measure"));
// Finally, clean up the entries.
performance.clearMarks();
performance.clearMeasures();
}, 1000);
}, 1000);
Specifications
Specification | Status | Comment |
---|---|---|
User Timing Level 2 The definition of 'measure()' in that specification. |
Working Draft | Clarifies measure() processing model. |
User Timing The definition of 'measure()' in that specification. |
Recommendation | Basic definition. |
Browser compatibility
BCD tables only load in the browser