PerformanceNavigationTiming.unloadEventStart
This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.
The unloadEventStart
property returns a timestamp
representing the time value equal to the time immediately before the user agent starts the unload event of the previous document. If there is no previous document, this property returns 0
.
This property is Read only .
Syntax
perfEntry.unloadEventStart;
Return Value
A timestamp
representing the time value equal to the time immediately before the user agent starts the unload event of the previous document.
Example
The following example illustrates this property's usage.
function print_nav_timing_data() { // Use getEntriesByType() to just get the "navigation" events var perfEntries = performance.getEntriesByType("navigation"); for (var i=0; i < perfEntries.length; i++) { console.log("= Navigation entry[" + i + "]"); var p = perfEntries[i]; // dom Properties console.log("DOM content loaded = " + (p.domContentLoadedEventEnd - p.domContentLoadedEventStart)); console.log("DOM complete = " + p.domComplete); console.log("DOM interactive = " + p.interactive); // document load and unload time console.log("document load = " + (p.loadEventEnd - p.loadEventStart)); console.log("document unload = " + (p.unloadEventEnd - p.unloadEventStart)); // other properties console.log("type = " + p.type); console.log("redirectCount = " + p.redirectCount); } }
Specifications
Specification | Status | Comment |
---|---|---|
Navigation Timing Level 2 The definition of 'unloadEventStart' in that specification. |
Editor's Draft | Initial definition. |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support. | No support | No support | No support | No support | No support |
Feature | Android | Firefox Mobile (Gecko) | Firefox OS | IE Phone | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support. | No support | No support | No support | No support | No support | No support |
License
© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/api/performancenavigationtiming/unloadeventstart