PerformanceTiming

The PerformanceTiming interface contains properties that offer performance timing information for various events which occur during the loading and use of the current page. You get a PerformanceTiming object describing your page using the window.performance.timing property.

Properties

The PerformanceTiming interface doesn't inherit any properties.

These properties each describe the time at which a particular point in the page loading process was reached. Some correspond to DOM events; others describe the time at which internal browser operations of interest took place. Each time is provided in milliseconds.

These properties are listed in the order in which they occur during the navigation process.

PerformanceTiming.navigationStart Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, right after the prompt for unload terminates on the previous document in the same browsing context. If there is no previous document, this value will be the same as PerformanceTiming.fetchStart.
PerformanceTiming.unloadEventStart Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, the unload event has been thrown, indicating the time at which the previous document in the window began to unload. If there is no previous document, or if the previous document or one of the needed redirects is not of the same origin, the value returned is 0.
PerformanceTiming.unloadEventEnd Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, the unload event handler finishes. If there is no previous document, or if the previous document, or one of the needed redirects, is not of the same origin, the value returned is 0.
PerformanceTiming.redirectStart Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, the first HTTP redirect starts. If there is no redirect, or if one of the redirects is not of the same origin, the value returned is 0.
PerformanceTiming.redirectEnd Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, the last HTTP redirect is completed, that is when the last byte of the HTTP response has been received. If there is no redirect, or if one of the redirects is not of the same origin, the value returned is 0.
PerformanceTiming.fetchStart Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, the browser is ready to fetch the document using an HTTP request. This moment is before the check to any application cache.
PerformanceTiming.domainLookupStart Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, where the domain lookup starts. If a persistent connection is used, or the information is stored in a cache or a local resource, the value will be the same as PerformanceTiming.fetchStart.
PerformanceTiming.domainLookupEnd Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, where the domain lookup is finished. If a persistent connection is used, or the information is stored in a cache or a local resource, the value will be the same as PerformanceTiming.fetchStart.
PerformanceTiming.connectStart Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, where the request to open a connection is sent to the network. If the transport layer reports an error and the connection establishment is started again, the last connection establishment start time is given. If a persistent connection is used, the value will be the same as PerformanceTiming.fetchStart.
PerformanceTiming.connectEnd Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, where the connection is opened network. If the transport layer reports an error and the connection establishment is started again, the last connection establishment end time is given. If a persistent connection is used, the value will be the same as PerformanceTiming.fetchStart. A connection is considered as opened when all secure connection handshake, or SOCKS authentication, is terminated.
PerformanceTiming.secureConnectionStart Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, where the secure connection handshake starts. If no such connection is requested, it returns 0.
PerformanceTiming.requestStart Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, when the browser sent the request to obtain the actual document, from the server or from a cache. If the transport layer fails after the start of the request and the connection is reopened, this property will be set to the time corresponding to the new request.
PerformanceTiming.responseStart Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, when the browser received the first byte of the response, from the server from a cache, or from a local resource.
PerformanceTiming.responseEnd Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, when the browser received the last byte of the response, or when the connection is closed if this happened first, from the server, the cache, or from a local resource.
PerformanceTiming.domLoading Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, when the parser started its work, that is when its Document.readyState changes to 'loading' and the corresponding readystatechange event is thrown.
PerformanceTiming.domInteractive Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, when the parser finished its work on the main document, that is when its Document.readyState changes to 'interactive' and the corresponding readystatechange event is thrown.
PerformanceTiming.domContentLoadedEventStart Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, right before the parser sent the DOMContentLoaded event, that is right after all the scripts that need to be executed right after parsing has been executed.
PerformanceTiming.domContentLoadedEventEnd Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, right after all the scripts that need to be executed as soon as possible, in order or not, has been executed.
PerformanceTiming.domComplete Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, when the parser finished its work on the main document, that is when its Document.readyState changes to 'complete' and the corresponding readystatechange event is thrown.
PerformanceTiming.loadEventStart Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, when the load event was sent for the current document. If this event has not yet been sent, it returns 0.
PerformanceTiming.loadEventEnd Read only
Is an unsigned long long representing the moment, in milliseconds since the UNIX epoch, when the load event handler terminated, that is when the load event is completed. If this event has not yet been sent, or is not yet completed, it returns 0.

Methods

The PerformanceTiming interface doesn't inherit any methods.

PerformanceTiming.toJSON()
Returns a JSON object representing this PerformanceTiming object.

Specifications

Specification Status Comment
Navigation Timing
The definition of 'PerformanceTiming' in that specification.
Recommendation Initial definition.

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 6.0 12.0 7.0 (7.0) 9.0 15.0 8.0
secureConnectionStart 6.0 (Yes) 56 (56) 9.0 15.0 9.0
toJSON() 45.0 ? 25.0 (25.0) 9.0 No support (Yes)
Feature Android Edge Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support 4.0 (Yes) 7.0 (7.0) 9.0 15.0 9.2
secureConnectionStart No support (Yes) 56.0 (56) 9.0 15.0 9.0
toJSON() No support ? 25.0 (25.0)   No support (Yes)

See also

Document Tags and Contributors

 Last updated by: Victor_Homyakov,