I am trying to build a small html5 app for Ubuntu touch. In general it is rather difficult to handle the html5 code. The design guide gives a lot of suggestions how to build an app, but neither the documentation nor the tutorials descibe how to implement these elements.
Currently I just want to add a search component to the header as suggested in the design guidelines:

My header uses a Tab navigation:
<header data-role="header" id="xxx">
<ul data-role="tabs">
<li data-role="tabitem" data-page="maintab">Main </li>
<li data-role="tabitem" data-page="anotherpage">Favorites</li>
</ul>
</header>
My question is how to add a search field to the header, when the header is only defined as a list?