Threading for iframe elements in IE

Question

Of the following, which are not run in the same thread as the current page in IE8?

• An iframe with the same domain as the current page.
• An iframe with a sub-domain of the current page's domain.
• An iframe with a super-domain of the current page's domain.
• An iframe with a completely different domain from the current page.

I want to know this for implementing Web Workers in IE that are in separate threads.

Edit: Is there any way to have a window in another thread in IE to postMessage to?

Answer 1

The IE threading is not tied to the domain of the resource. An iframe DOM is build and is tied to the same thread as the main browser document.

Answer 2

As Franci mentioned, using an iframe will not get you a new thread. However, you can "simulate" multi-threading with setTimeout and callbacks:

• "Multi-threading in JavaScript": http://articles.sitepoint.com/article/multi-threading-javascript
• The fakeworker.js (An implementation of Web Workers using this setTimeout trick): http://code.google.com/p/fakeworker-js/