From the FAQ:
Where can additional JavaScript be placed?
Additional JavaScript can be placed in the
PAGE_CONTAINER,
page_container_js_head or
page_container_js_body templates. If
PAGE_CONTAINER is used, it can be placed anywhere in the template. If
page_container_js_head is used, it will be included in the head section of
PAGE_CONTAINER. If
page_container_js_body is used, it will be included in the body section of
PAGE_CONTAINER, after the footer. It depends on the JavaScript to a large extent; some require to be placed in the head, some in the body.
How do I include a JavaScript file?
Code:
<xen:require js="name_of_javascript_file.js" />