Getting user specified javascript executed for all pages

Question

Is there a way for the user to get browsers to load a (small) piece of Javascript code for every page they view?

Answer 1

Depends on the browser. In Opera you can use UserJS to do this, and a user can specify where it applies and what it does. It is entirely up to the user to set this up. This can be used for overriding annoying behaviour on a site, adding your own customisations (until Opera 10, UserJS was the most common way of incorporating automatic spell-checking), or getting sites to work (Opera use a file called Browser.js for this to help make broken/buggy/unfriendly sites work in the browser)

Answer 2

The user can do it with a firefox plugin, called greasemonkey. The server cant do that.

Answer 3

If you really wanted to, you could probably let them submit their JS, store it, and run it with PHP. I didn't really test that out, but this little snippet worked, so I'd imagine you could do it:

<?php

$js = <<< HERE

<script type="text/javascript">

    document.write("hello world");

</script>

HERE;

echo $js;

?>