demo · v132
firstResponseHeadersStart — live observer
Fetch a resource and inspect the new PerformanceResourceTiming.firstResponseHeadersStart field next to responseStart. With early hints (103), they differ; without, they are equal.
checking support…
| field | ms | note |
|---|---|---|
| startTime | — | fetch began |
| requestStart | — | request sent |
| firstResponseHeadersStart | — | NEW: first (possibly 103) headers seen |
| responseStart | — | final-response headers reverted to pre-103 meaning |
| responseEnd | — | body finished |
see also
- firstResponseHeadersStart — feature index
- ChromeStatus entry
- Spec