Google Chrome Extension http://code.google.com/p/script-cover/
Some things to note:
If the program needs data to detect if the code is covered, it will need
it; however if an object is used/associated with a program, it seems to
automatically associate it and attempt coverage with it and all its
The plugin will need to be disabled for casual surfing, otherwise it
analyzes the JS of each page you visit and can slow surfing down.
The plugin does not work offline / locally - it will analyze jslint.com,
but it won't analyze c:\jslint\index.html
The plugin is somewhat unstable, seems to crash the page a lot for me
when doing very heavy work.
Otherwise the plugin is good at detecting logical fallacies and dead
code that JSLint is otherwise incapable of detecting.
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