The JavaScript context of a custom element

Hello public-webapps,

I have been following along with web components, and am really excited
about the potential.

However, I just realized that unlike the DOM and CSS, there is no real
isolation for JavaScript in a custom element. In particular, the global
scope is shared.

This seems really unfortunate to me, and limits the ability of element
authors to create robustly reusable components.

I would like to suggest that custom elements have the ability to ask for a
separate global scope for their JavaScript. This would be analogous to what
happens today when you have multiple script-connected frames on the same
origin.

Has there been any thought along these lines in the past?

Thanks,

- a