The fetchStart
read-only property represents a timestamp
immediately before the browser starts to fetch the resource.
If there are HTTP redirects the property returns the time immediately before the user agent starts to fetch the final resource in the redirection.
Note: This feature is available in Web Workers.
Syntax
resource.fetchStart;
Return value
A DOMHighResTimeStamp
immediately before the browser starts to fetch the resource.
Example
In the following example, the value of the *Start
and *End
properties of all "resource
" type
events are logged.
function print_PerformanceEntries() {
// Use getEntriesByType() to just get the "resource" events
var p = performance.getEntriesByType("resource");
for (var i=0; i < p.length; i++) {
print_start_and_end_properties(p[i]);
}
}
function print_start_and_end_properties(perfEntry) {
// Print timestamps of the PerformanceEntry *start and *end properties
properties = ["connectStart", "connectEnd",
"domainLookupStart", "domainLookupEnd",
"fetchStart",
"redirectStart", "redirectEnd",
"requestStart",
"responseStart", "responseEnd",
"secureConnectionStart"];
for (var i=0; i < properties.length; i++) {
// check each property
var supported = properties[i] in perfEntry;
if (supported) {
var value = perfEntry[properties[i]];
console.log("... " + properties[i] + " = " + value);
} else {
console.log("... " + properties[i] + " = NOT supported");
}
}
}
Specifications
Specification | Status | Comment |
Resource Timing Level 1The definition of 'fetchStart' in that specification. | Candidate Recommendation | Initial definition. |
Browser compatibility
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Update compatibility data on GitHub
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
fetchStart
|
Chrome
Full support 43 |
Edge
Full support 12 |
Firefox
Full support 40 |
IE
No support No |
Opera
Full support 30 |
Safari
Full support 11 |
WebView Android
Full support 43 |
Chrome Android
Full support 43 |
Firefox Android
Full support 42 |
Opera Android
Full support 30 |
Safari iOS
Full support 11 |
Samsung Internet Android
Full support 4.0 |
Legend
- Full support
- Full support
- No support
- No support
PerformanceResourceTiming.fetchStart by Mozilla Contributors is licensed under CC-BY-SA 2.5.