Tayrakit is a browser toolkit using Tayra templating language. Most popular toolkits are written entirely as javascript libraries that are normally fetched when a page gets loaded. Tayrakit adapts the opposite way. Widgets, also called as template plugins, are authored using a templating language so that html parts are kept as HTML, css parts are kept as CSS and JavaScript is used only where it is required - for event callbacks :)
Tayrakit under development - you can hack the code, contribute back with github. Note that the orginal repository is maintained with mercurial and uses hg-git plugin to publish it on github.