Lift keeps the page as an XML data structure throughout the rendering process. This allows Lift to rewrite the web page at different rendering phases. After the rendering is complete, Lift looks for all the <head/> tags in the <body> tag. Lift takes the contents of each <head/> tag, removes any duplicates and places the resulting tags in the top level <head/> tag.

So, if you have the following code in your page:

<span>
  <head>
    <script type="text/javascript" src="/classpath/jquery.js"/>
  </head>
  do some jQuery stuff here
</span>


<span>
  <head>
    <script type="text/javascript" src="/classpath/jquery.js"/>
  </head>
  Do some other jQuery stuff here
</span>

Lift will put a single <script type="text/javascript" src="/classpath/jquery.js"/> into the <head/> of the page.