Code coverage question

Question

The problem i am trying to solve is to determine what %age of code is being "touched" by the tests written by my team for an application written almost entirely using Javascript and Javascript libraries like EXTJS etc.

Now I would like to know if there is any tool out there - preferably open source - which lets us analyze the code coverage.

Pointers to these tools would be highly appreciated.

 

PS - I did search for these tools before posting on this forum but I didnt get very far with the search results.

 

Thanks,

K.