You wouldn’t download a new car each time you want to download a new car.

The NoScript extension will properly do this. The extension blocks domains from running scripts except those you’ve whitelisted. There’s a drop down that displays a list of domains from which the page wishes to run scripts. It makes much of the web a pain to use, though. I sometimes have to go through a loop of whitelisting a subset of domains which want to run followed by a page refresh until the page works. Javascript is often not optional. If you had to live like Richard Stallman professes you should, you’d probably have to join the Amish.