How to provide ECMAScript 5 (ES 5)-shim?

Question

ECMAScript Fifth Edition (released December 2009) introduces a bunch of new methods (see this table for details). However, there still are older browsers out there which do not

Answer 1

This seems to work for me:

<!--[if lt IE 9]><script src="java/es5-shim.min.js"></script><![endif]-->

Answer 2

ES5-Shim will only shim parts that the browsers don't implement, so just give it to all browsers. It'll handle the detection of what needs to be shimmed and what doesn't.

But pay attention to the caveats listed on what shims don't work correctly in some instances. I've had issues with that in the past and it causes a ton of pain until you realize the answer was super simple...

Answer 3

At present, the solution that works best with ES5-Shim is to use the library in all environments and allow it to detect which features it needs to patch at run-time. It would be even better to deliver it from a community CDN to maximize cross-site cache hits.

That being said, there is an open opportunity to create systems that combines feature detection, agent fingerprinting, and dynamic bundling to automatically generate and deliver targeted shim subsets. The scope of the problem extends far beyond just ES5-Shim and could be applied to all sorts of shims.