PerformanceEntry.duration
The duration
property returns a
timestamp
that is the duration of the
performance entry
.
Note: This feature is available in Web Workers
The value returned by this property depends on the performance entry's
type
:
-
"
frame
" - returns atimestamp
indicating the difference between thestartTime
s of two successive frames. - "
mark
" - returns "0
" (a mark has no duration). -
"
measure
" - returns thetimestamp
that is the duration of the measure. -
"
navigation
" - returns thetimestamp
that is the difference between thePerformanceNavigationTiming.loadEventEnd
andPerformanceEntry.startTime
properties, respectively. -
"
resource
" - returns the difference between the resource'sresponseEnd
timestamp
and itsstartTime
timestamp
.
This property is Read only .
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 PerformanceResourceTiming.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 |
---|
Performance Timeline # dom-performanceentry-duration |
Browser compatibility
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