HTTP

HTTP is the protocol under every page, image, script and fetch: the browser sends a request (method, URL, headers, maybe a body) and the server sends back a response (status, headers, maybe a body). That meaning hasn't changed since the 1990s. How it's carried has: first as lines of text, now as binary frames. Notes.

1. One request, three versions

The same request, reading a Rooms room, and its reply, as each version of HTTP carries them.





2. This page's requests


A page can't see HTTP's bytes, but the browser keeps a record of every
request it made: which protocol, how the time was spent, how many bytes
came over the network. Each button makes one request and adds a row.



  
  
  
  



The file is this repo's README.md,
from the same server as this page.




Time:
  DNS connect
  TLS waiting for the server
  download



3. This page's response headers


The headers the server sent with this page, read with a
HEAD request to the page's own URL. Same-origin, so the page
may read them all.