I especially like the VS2012 web inspector - it's like having Firebug or Chrome Inspector plugged into the live code, html, and css, so any changes you make are saved.
This changes EVERYTHING.
Are you being sarcastic? Low quality comment nonetheless.
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To parent of his comment, what do you mean exactly? Firebug already lets you change code and see the results immediately.
Firebug doesn't sync the changes back to the original code.
Sync the changes to the source file? How would any client do that without write permissions? Or is that the point?
you might want to take a look at https://github.com/adobe/brackets/
can't say i'm particularly thrilled at the idea though