Please see the following link for good practics
You can find out example here https://github.com/rhomobile/rho-samples
That said, you can load view-specific JS if you are using jQuery Mobile. The correct place to put it is inside of the <div data-role-"page"> but at the end, just before the closing </div>.
I think above you meant "external scripts", not "external style sheets"...
I do some pre-processing (using a rake script) before build, and normally concatenate and minify all of my JS into one file. (Also do this with style sheets.)
I am not using JQuery Mobile. The bulk of development is being done in Ruby; this means there is not a lot of JS.
Thanks a lot for this information it has been very helpful