Simon Willison’s Weblog

xssinterface (via) Clever JavaScript library for implementing opt-in cross-domain messaging in JavaScript (allowing communication between pages and iframes on different domains). Uses HTML 5’s postMessage API if available, otherwise falls back on either Google Gears or a clever cookie hack. 5th March 2008, 12:08 am

Cross-Site XMLHttpRequest (via) “Firefox 3 implements the W3C Access Control working draft, which gives you the ability to do XMLHttpRequests to other web sites”—you can mark a document as available for cross-domain requests using either an Access-Control HTTP header or an XML processing instruction. 9th January 2008, 11:57 pm

hasAccount. Stuart proposes a light-weight API for letting any site know if a user has an account (and is signed in) on another service. I wouldn’t want to deploy this without being confident that my CSRF protection was in order. 28th September 2007, 9:10 am

Google AJAX Feed API (via) Simple cross-domain proxy to allow JavaScript to access any publically addressable syndication feed, with the same logic as Google Reader providing normalisation. 18th April 2007, 5:29 pm

XMLHttpRequests using an IFrame Proxy (via) Another scary hack abstracted away by Dojo. 1st August 2006, 5:40 pm