Detect browser support for cross-domain XMLHttpRequests?

Question

I\'m working on some Javascript that makes use of Firefox 3.5\'s ability to perform cross-domain XMLHttpRequests… But I\'d like to fail gracefully if they aren\'t supported.

Answer 1

You might want to look at EasyXDM, which wraps cross-browser quirks and provides an easy-to-use API for communicating in client script between different domains using the best available mechanism for that browser (e.g. postMessage if available, other mechanisms if not).

Clearly that library has solved the browser-capabilities detection problem, so you can benefit from their experience. :-)