Lessons from production - Limitations of today's script caching techniques

[Jason Benterou]

As Chris mentioned in his recent post, DominateJS is an asynchronous
loader inspired by ControlJS, with robust document.write emulation,
supporting AdSense and other challenging scenarios. At CloudFlare,
we've made the tool available under the marketing name "Rocket Script
(beta)". Over 1,000 websites use Rocket Script in production today.

One lesson learned: the Object method of pre-caching javascript files
has some severe limitations, while the Image technique is more robust
than we thought. We've moved away from the Object technique in all
browsers except Firefox on Windows.

Our findings are described in this article. Test cases included.

http://static.jtwb.dotcloud.com/research/preloaders.html

-Jason

[Steve Souders]

I wrote a long comment on the blog. I tested two of the issues that were
mentioned and failed to reproduce the results found in the post. I'm
wondering if there's an issue in the way cache was verified.

-Steve