[jeremiep]

Why not just use underscore.js then? It uses Array.prototype.map for _.map if present and fallback to its own implementation otherwise.

[yuhong]

It is far from the only example (my favorite is the lack of XHTML support).

[alanh]

> lack of XHTML support

I believed IE8 reads XHTML just fine — are you referring to its inability to handle HTML content delivered with an `application/xml+xhtml` Content-Type header (IIRC)?

[yuhong]

Yes.