Google Chrome Developer Tools
code.google.com
code.google.com
Dev tools is an excellent tool for web developers, and as far as I know, no one is using it because of Firefox and Firebug. I'm not saying they aren't good tools: they are. It's just that I personally prefer Chrome over Firefox as a browser, and I'm really glad I found this documentation resource.
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You totally can view the response, just go to the 'Resources' tab, choose 'XHR' from the top bar (or not, but it's easier). Now cause a request. You'll see it pop up in the list on the left and you can click it to see headers/params and the response.
For instance, when an XHR response is returned as "Content-Type:text/html; charset=UTF-8", I still see raw HTML in the content pane: http://grab.by/7SXg
I just end up using Firebug Lite instead when I need to do this, but it's really clunky.
However the dev channel has a tendency to break JS breakpointing. It seems like I can never fully delete some breakpoints.
Chrome dev tools have come a long way though. I use Chrome as my main browser now for both surfing and dev, and although I miss the snappiness of Firebug, Chrome's dev tools are just as good, if not better.
Look familiar? :)
Not only is extension development much more fun (you can load unbundled extensions directly from the source directory, reload it to load the updates source code with one click, and there is no need to restart the browser at all). But one of the best features is that when you get some element from the DOM of the current page, and log it or any of the children elements to the developer console and hover over it, Chrome highlights that particular part on the website itself. This is just so helpful!
One thing Firebug does that I can't find in WebKit's developer tools: in Firebug, when you select an element and switch to the "Layout" tab, mousing over the various measurements will draw on-screen rulers and guides that show how the element lines up with other items on the page.
I think it would be nice to have debugging support for JS code in those cases when it's evaluated from a string instead of loaded using a <script> tag.
Chrome Developer Tools no longer has a 'Network' icon / function and the 'Storage' icon / function is not documented.
I believe Network was subsumed into Resources recently.
Personally, I have found the excellent CDT to be essentially self-documenting.