How to include javascript from a CDN source using smarty

How do you include Javascript from a CDN source using Smarty? We have code such as the开发者_运维百科 following for including it from a file on the web server, but I want to include it from a CDN instead.

{javascript file="prototype.js" priority=20}

When I access the Smarty documentation at http://www.smarty.net/manual/en/ "javascript" cannot be found anywhere within the page, and when I try to search the documentation the results from the following are not at all helpful: http://www.smarty.net/manual/en/search.php?query=javascript

Why not just include the remote .js file, using the HTML <script> tag ?

Something like that, I suppose :

<script 
  src="http://ajax.googleapis.com/ajax/libs/prototype/1.6.1.0/prototype.js"
  type="text/javascript">
</script>

(Well, you can use another CDN than google's of course -- I took that URL as an example)

I've never heard of that {javascript} tag for smarty; maybe it's a plugin that's been defined in your project?

We use the following pattern:

<script src="{$page.cdn}prototype.js" type="text/javascript></script>

Where $page contains information that changes based on the environment.

Development server:

$page.cdn = /resources/

Production server:

$page.cdn = http://cdn.domain.com/app