mark(name)
mark(name, markOptions)
Parameters
name
-
A string representing the name of the mark. Must not be the same name as one of the properties of the deprecated
PerformanceTiming
interface. markOptions
Optional-
An object for specifying a timestamp and additional metadata for the mark.
detail
Optional-
Arbitrary metadata to include in the mark. Defaults to
null
. Must be structured-cloneable. startTime
Optional
Return value
The PerformanceMark
entry that was created.
Exceptions
PerformanceTiming
interface. See the example below.TypeError
: Thrown ifstartTime
is negative.
Examples
Creating named markers
The following example uses mark()
to create named PerformanceMark
object that has been created.
performance.mark("login-started");
performance.mark("login-started");
performance.mark("login-finished");
performance.mark("form-sent");
const videoMarker = performance.mark("video-loaded");
Creating markers with details
The performance mark is configurable using the markOptions
object where you can put additional information in the detail
property, which can be of any type.
performance.mark("login-started", {
detail: "Login started using the login button in the top menu.",
});
performance.mark("login-started", {
detail: { htmlElement: myElement.id },
});
Creating markers with a different start time
The default timestamp of the mark()
method is performance.now()
. You can set it to a different time using the startTime
option in markOptions
.
performance.mark("start-checkout", {
startTime: 20.0,
});
performance.mark("login-button-pressed", {
startTime: myEvent.timeStamp,
});
Reserved names
Note in order to maintain backwards compatibility, names that are part of the deprecated PerformanceTiming
interface can't be used. The following example throws:
performance.mark("navigationStart");
/ SyntaxError: "navigationStart" is part of
/ the PerformanceTiming interface,
/ and cannot be used as a mark name