bookmarklet-load-script.js

(function(src) {
    document.body.appendChild(document.createElement('script')).setAttribute('src', src);
})(prompt("Script URL to load", "http://example.com/script.js"));

// You could drop the self executing function now src is at the end of the line, it's just as easy to edit.

What's wrong with local variables? How is passing in a document any shorter? Surely it makes the overall code longer even if the function is shorter?

Fair point, I was getting overly code-golfy. Not that passing document in helps, you're right.

Nothing against local vars, but i like the style of passing args, and avoiding a var declaration. All very cosmetic. Just re-writing it now to be cleaner and shorter.

I like the pattern of passing in variables for dependency injection to make functions more reusable/testable, but not sure there's a benefit in this case. You only care about the local scope inside the function, so a local variable is probably the best solution. Fore!