Can
No, this would allow to retrieve the contents of any URL, which would break some security policies. (This would be an equivalent of an ajax get request without same-domain checks.)
However, since foo.js
is on the same domain than the page you can fetch it with an ajax request. Example with jQuery:
$.get('foo.js', function(source_code) {
alert('foo.js contains ' + source_code);
});
No, not directly for fundamental security reasons.
The fact that you've tagged this with Ajax implies that you're trying to use this as a way to retrieve data. If so, the closest similar approach is JSONP, in which the newly loaded script invokes a method to pass data back to the parent document.