Syntax:

<?script [type="text/javascript"] [src="''uri''"] [charset="''encoding''"]
  [content="''javascript snippet''"] [if="..."] [unless="..."]?>

It tells ZK to generate a <script> inside <head>.

`after ZK default JavaScript and CSS files. Thus, it can be used to override what is defined in ZK default JavaScript code. Currently, only HTML-based clients (so-called browsers) support it. Furthermore, an HTML SCRIPT tag is generated for each of these declarations.

You can specify whatever attributes you like; it is up to the browser to interpret. ZK only evaluates the if and unless attributes, and encodes the URI of the href and src attribute (by use of org.zkoss.zk.ui.Execution#encodeURL(java.lang.String)). So you can specify an absolute or relative path. ZK generates all other attributes directly to the client.

<?script src="/js/foo.js"?>
<?script content="var foo = true; if (zk.ie) doSomething();"?>

 <window title="My App">
     My content
 </window>

As shown above, the attribute value could span multiple lines.

Alternatives

Alternatively, you could use the script component to embed JavaScript code. The script component supports more features such as defer, but it has some memory footprint at the server (since it is a component).