Web-based JavaScript Debugger

I have an idea for a project that has to do with helping people learn to program. One of the things I think would be cool would be to have a place on the site where you can edit JavaScript code in real time in your browser.

I know there are a number of web-based JavaScript editors, but I haven't been able to find out if there are any tools that let you debug JavaScript from your browser. I think being able to step through your code is a valuable learning experience for people who are new to programming. It seems like something along those lines should be possible, though.

I o开发者_开发技巧riginally thought you could use something like Firebug Lite: http://getfirebug.com/firebuglite, but they don't support debugging. Is this just too hard of a problem to solve in JavaScript?

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I suggest you try Cloud9. It is a full-featured web based IDE for Javascript, which includes a great debugger. It is free for open source projects, which I imagine would include most learning purposes.

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Why not just use the build in Javascript console from the browser? Every modern browser has this feature.