jquery-archive/jquery-metadata

jQuery Metadata Plugin

By John Resig

This plugin is capable of silently, and automatically, extracting metadata 
from classes, random attributes, and child elements.

For example, you can do:
<li class="someclass {some: 'data'} anotherclass">...</li>
OR
<li data="{some:'random', json: 'data'}">...</li>
OR
<li><script type="data">{some:"json",data:true}</script> ...</li>

The default is the first method, but you can always change it by twiddling 
the options. This means that there is at least one option here that can 
appease you.

There's also a bunch of options (like loading data into a single property 
and the ability to ignore braces {}).