Et WebKit vous aide quand même pas mal.

Web Inspector, the popular open source web development tool for Safari web browser, is now ten years old. For a decade now, Web Inspector has helped developers prototype, inspect and debug their code on iOS and Mac devices.  It began as a simple tool, lacking even a basic console, and capable of only offering the DOM tree and style rules. However, over the course of ten years, Web Inspector has evolved into a big project, and today, it is an integral part of every web developer's workflow who needs to work with the Safari web browser. The most interesting part is that Web Inspector, in itself, has been open source ever since its birth back in 2006. With each major update of Safari, Web Inspector too got an overhaul, such as the major UI redesign in 2008. Last year, Web Inspector added many new changes and updates to its core, such as enhanced JavaScript support, better queries and styling, better frame rendering and many new interesting additions. As of now, Web Inspector does not seem to have any decent alternative and as such, this open source web development tool built within the Safari web browser is going strong. Are you a user of Web Inspector? If not, and if you do code often for iOS or Mac devices, you should give it a spin. And if you are an existing user, how has your experience been? Share your views in the comments below. Read More at Web Inspector Turns 10 http://dlvr.it/DKvrXv www.regulardomainname.com

Firefox 36 was just uplifted to the Developer Edition channel, so let’s take a look at the most important Developer Tools changes in this release. ...

Safari 7 Web Inspector - When disabling an element's CSS style from the web inspector, it adds comment tags around it and changes the color to green, just like a real CSS comment.

There's an easy way to get firebug-like tools in Safari.  From the terminal, run defaults write com.apple.Safari WebKitDeveloperExtras -bool true Now you can examine html and css for the page you're on similar to how you would with firebug. Position your mouse pointer over an element you want to look at. Right-click --> Inspect Element.  Up pops a console, with the HTML for the element you were hovering over.  CSS for that element is to the right of the HTML. **To edit the css, you have to edit the properties and values for the html element below the "Computed Styles".  Editing the computed styles does nothing. Below the computed styles should be the element you want. Double click to access the property and it's values. To add a new property, double click an existing property and add a semi-colon after it.  Then add your new rule. While you're still in the current attribute (cursor is blinking), see your CSS take effect by pressing enter or click outside of the current property/value in order to save your edits. There is an additional menu to go along with other features too.  Expose this menu by going to Preferences -> Advanced -> Check the box "Show Develop Menu in Menu Bar". Here are some of the other dev features apple has added to Safari, http://www.apple.com/safari/features.html#developer

I got used Safari's Web Inspectore specially because it made my battery life longer then Firefox; and I spend many hours per day in a train. But the Safari 6 Web Inspector is a total super unusable mess. It's simply not possible to get work done. With good old Firebug I get my stuff 6 times faster done. Well, that's why I have to post this link which sums it up.

John on Web Inspector.