First, and most importantly: Use version control and push to a remote server at regular intervals. There are multiple free options available, such as BitBucket. You should never have put yourself in this situation.
www content in PhoneGap applications is interpreted at run time, you should be able to recover it from a device by syncing it to iTunes, then dragging the application out of iTunes as an ipa file. The ipa file is just a zip file following some particular conventions, so rename it to .zip and decompress it to get the files in the application bundle.
And finally, because it's so important: Use version control and push to a remote server at regular intervals. A programmer without version control is like a painter without overalls or a bicyclist without a helmet.