following the HTTP dialog in curl and browsers like Firefox and Chrome

I honestly wonder, why curl and the browsers do not show you the HTTP status code during your web interactions "by default".

Usually I personally employ curl on the command line with --write-out '… %{http_code} %{url_effective}  …'.

Add-ons for Firefox:

• LiveHTTPheaders
• HTTP Resource Test

Add-ons for Chrome:

• HTTP Headers
• REST console
• Advanced Rest client
• this search will lead you to quite some different tools

Actually in Chrome you can follow the description here, it only employs internal means.

browsers and their developer tools

(from Head First jQuery)

• Google Chrome: http://code.google.com/chrome/devtools/docs/overview.html
• Firefox’s Firebug: http://getfirebug.com/wiki/index.php/FAQ
• Safari: http://www.apple.com/safari/features.html#developer
• Internet Explorer 8: http://msdn.microsoft.com/en-us/library/dd565628(v=vs.85).aspx
• Internet Explorer 9: http://msdn.microsoft.com/en-us/ie/aa740478
• Opera’s Dragonfly: http://www.opera.com/dragonfly/

browserling - interactive cross-browser testing in your browser

browserling - interactive cross-browser testing in your browser: "Cross-browser testing from thecomfortof your browser!"