ThePerformanceTiming interface is a legacy interface kept for backwards compatibility and contains properties that offer performance timing information for various events which occur during the loading and use of the current page. You get aPerformanceTiming object describing your page using thewindow.performance.timing property.

Instance properties

ThePerformanceTiming 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 as a number representing the moment, in milliseconds since the UNIX epoch.

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

PerformanceTiming.navigationStartRead onlyDeprecated

When 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 asPerformanceTiming.fetchStart.

PerformanceTiming.unloadEventStartRead onlyDeprecated

When theunload 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 is0.

PerformanceTiming.unloadEventEndRead onlyDeprecated

When theunload 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 is0.

PerformanceTiming.redirectStartRead onlyDeprecated

When 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 is0.

PerformanceTiming.redirectEndRead onlyDeprecated

When 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 is0.

PerformanceTiming.fetchStartRead onlyDeprecated

When the browser is ready to fetch the document using an HTTP request. This moment isbefore the check to any application cache.

PerformanceTiming.domainLookupStartRead onlyDeprecated

When 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 asPerformanceTiming.fetchStart.

PerformanceTiming.domainLookupEndRead onlyDeprecated

When 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 asPerformanceTiming.fetchStart.

PerformanceTiming.connectStartRead onlyDeprecated

When 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 asPerformanceTiming.fetchStart.

PerformanceTiming.connectEndRead onlyDeprecated

When 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 asPerformanceTiming.fetchStart. A connection is considered as opened when all secure connection handshake, or SOCKS authentication, is terminated.

PerformanceTiming.secureConnectionStartRead onlyDeprecated

When the secure connection handshake starts. If no such connection is requested, it returns0.

PerformanceTiming.requestStartRead onlyDeprecated

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.responseStartRead onlyDeprecated

When the browser received the first byte of the response, from the server from a cache, or from a local resource.

PerformanceTiming.responseEndRead onlyDeprecated

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.domLoadingRead onlyDeprecated

When the parser started its work, that is when itsDocument.readyState changes to'loading' and the correspondingreadystatechange event is thrown.

PerformanceTiming.domInteractiveRead onlyDeprecated

When the parser finished its work on the main document, that is when itsDocument.readyState changes to'interactive' and the correspondingreadystatechange event is thrown.

PerformanceTiming.domContentLoadedEventStartRead onlyDeprecated

Right before the parser sent theDOMContentLoaded event, that is right after all the scripts that need to be executed right after parsing have been executed.

PerformanceTiming.domContentLoadedEventEndRead onlyDeprecated

Right after all the scripts that need to be executed as soon as possible, in order or not, have been executed.

PerformanceTiming.domCompleteRead onlyDeprecated

When the parser finished its work on the main document, that is when itsDocument.readyState changes to'complete' and the correspondingreadystatechange event is thrown.

PerformanceTiming.loadEventStartRead onlyDeprecated

When theload event was sent for the current document. If this event has not yet been sent, it returns0.

PerformanceTiming.loadEventEndRead onlyDeprecated

When theload 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 returns0.

Instance methods

ThePerformanceTiminginterface doesn't inherit any methods.

PerformanceTiming.toJSON()Deprecated

Returns aJSON object representing thisPerformanceTiming object.

Specifications

Browser compatibility

See also

• ThePerformance.timing property that creates such an object.
• PerformanceNavigationTiming (part of Navigation Timing Level 2) that has superseded this API.