Question

I successfully loaded a script into an existing page by bookmarklet.
(Can tell my a success js request seen in firebug)
The next step is to make the script run.

This is what my external script looks like.

javascript: (function () {
    alert('hello world');
}

and I don’t see the alert. Missing something?

Answer 1

The function is not called and you have a syntax error (missing closing bracket )). You can make it an immediate executed function:

javascript: (function () {
    alert('hello world');
}())

Update: If you are actually injecting a script tag into the head via the bookmarklet, then you don’t need to have javascript: in the file.