4 ms·
With some forms of caching it's much simpler: the browser sends an ETag or If-Modified-Since and the server is supposed to return 304 Not Modified to optimize t
by floatboth 6y ago
With some forms of caching it's much simpler: the browser sends an ETag or If-Modified-Since and the server is supposed to return 304 Not Modified to optimize the load if the cached resource is still valid.
- kortilla 6y agoBut from JavaScript I don’t think you can see that. You just get the end result of the image being served to you. You have to infer it from timing.
- megous 6y agohttps://megous.com/dl/tmp/705dc9a2477d1f95.png https://megous.com/dl/tmp/705dc9a2477d1f95.png For cross-origin, you'd add CORS.