alert ('do something');
I don't think why you want CDN for jQuery, all the files will be hosted on the user's machine.
I'd suggest to include the jQuery JS and your popup.js in your popup.html:
My understanding is that it's not necessary to use background.js. You can have your code in popup.js instead. Therefore you won't need to include anything in the manifest file either.
Ok then, try @Archer's solution above, that might be a better one for you.
Then in popup.js you should be able to access jQuery, so your eventHandler would look like this:
good point about not needing CDN. What is popup.html? I don't know what that is. To clarify, the onclick is triggered when the user clicks on the page action's icon.
ok but for my extension, I don't want a popup.
popup.html is the html content that 'pops up' when you click your extension icon in Chrome.