Do you localize your javascript to the page, or have a master ‘application.js’ or similar?
If it’s the latter, what is the best practice to make sure your .js isn’t executing on the wrong pages?
EDIT: by javascript I mean custom javascript you write as a developer, not js libraries. I can’t imagine anyone would copy/paste the jQuery source into their page but you never know.
Putting all your js in one file can help performance (only one request versus several). And if you’re using a content distribution network like Akamai it improves your cache hit ratio. Also, always throw inline js at the very bottom of the page (just above the body tag) because that is executed synchronously and can delay your page from rendering.
And yes, if one of the js files you are using is also hosted at google, make sure to use that one.