The description
read-only property returns a string value of the server-specified metric description, or an empty string.
The description
read-only property returns a string value of the server-specified metric description, or an empty string.
A string.
Server timing metrics require the server to send the Server-Timing
header. For example:
http
Server-Timing: cache;desc="Cache Read";dur=23.2
The serverTiming
entries can live on navigation
and resource
entries.
Example using a PerformanceObserver
, which notifies of new navigation
and resource
performance entries as they are recorded in the browser's performance timeline. Use the buffered
option to access entries from before the observer creation.
js
const observer = new PerformanceObserver((list) => { list.getEntries().forEach((entry) => { entry.serverTiming.forEach((serverEntry) => { console.log( `${serverEntry.name} (${serverEntry.description}) duration: ${serverEntry.duration}`, ); // Logs "cache (Cache Read) duration: 23.2" }); }); }); ["navigation", "resource"].forEach((type) => observer.observe({ type, buffered: true }), );
Example using Performance.getEntriesByType()
, which only shows navigation
and resource
performance entries present in the browser's performance timeline at the time you call this method:
js
for (const entryType of ["navigation", "resource"]) { for (const { name: url, serverTiming } of performance.getEntriesByType( entryType, )) { if (serverTiming) { for (const { name, description, duration } of serverTiming) { console.log(`${name} (${description}) duration: ${duration}`); // Logs "cache (Cache Read) duration: 23.2" } } } }
Specification |
---|
Server Timing # dom-performanceservertiming-description |
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
description |
65 | 79 | 61 | No | 52 | 16.4 | 65 | 65 | 61 | 47 | 16.4 | 9.0 |
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https://developer.mozilla.org/en-US/docs/Web/API/PerformanceServerTiming/description