In the process of converting a .NET rich application to Javascript. One of the GUI features folks liked a lot was to rearrange their application layout. In .NET this was accomplished via Sandock:
http://www.divelements.com/net/controls/sanddock/screenshots.aspx
Anything like this for Javascript?
The closest I know to that is the javascript library ExtJS. I've used it in a few projects very successfully since it allows you to create rich Web UIs very similar to windows UIs (or widgets).
The learning curve can be a bit steep though if you aren't that familiar with javascript, however the community is quick to respond and helpful.