Prototype DOM-traversal methods failing on HTML5 elements in IE < 9 using html5shiv

I'm using html5shiv 1.6.2 (latest) and Prototype v1.7 (latest).

So, html5shiv makes my <article>, <section> etc elements work nicely in IE < 9. They appear, I can style them etc. All good.

However, if I try to grab any such HTML5 elements using Prototype's DOM-traversal methods (e.g. down(), up()), then they always return undefined in IE8/IE7 (who cares about IE6?). For example:

<article id="foo">
    <div></div>
  开发者_高级运维  <section></section>
    <ul id="abc123"></ul>
</article>

..and then..

var bar = $('foo').down('div'); // works
var baz = $('foo').down('section'); // undefined

..and..

var theArticle = $('abc123').up('article'); // undefined

Anyone experienced such woes? Solutions/workarounds?

This appears to be down to a bug in the sizzlejs selector engine as coupled with Prototype 1.7, but it's fixed in later versions of sizzlejs. So, options are:

1. wait for next Prototype version (probably with newer sizzlejs)
2. go back to Prototype 1.6.x for now..