On: Measuring download speed by embedding a GIF inside...

[mmj]

  PS This system measured my connection speed as 20Mbps. Which is about 5x too large.
  
  
  GET /inet/ent_logon/Logon?redirectjsp=true HTTP/1.1
  
  HTTP/1.x 200 OK
  Content-Encoding: gzip

---

The page is gziped.

[mooism2 → mmj]

Perhaps a gif was used on the assumption that gzip wouldn't be able to further compress it.

[nikblack → mooism2]

no. since it is gzipped, there is no progressive download of the page and it is all downloaded at once and then executed. so startTime and endTime are measuring processor execution rather than download speed.

it is a flawed method. a better method would be to make an xmlhttprequest to an object of known size and compare the time to known times for known connection speeds. this method also has the advantage that you don't interrupt the page being loaded and don't interrupt the user experience since it is run in parallel.

[gojomo → nikblack]

since it is gzipped, there is no progressive download of the page

Gzipped data can be incrementally decompressed. Are you sure browsers download the entire page before starting decompression?

(Not that this would make the test much better; I agree it has numerous flaws. Just curious about what browsers actually do.)