Comment 5 for bug 113201

I don't know if we should do a lot to encourage the use of DNS-calling PAC
functions. Ari Luotonen, the designer of PAC, had said on occassion that he
wanted to end-of-life these functions because the failure conditions caused
excessive delays. Many PAC file writers do not understand DNS well enought to
understand the pitfalls. I saw one large bank call isResolvable() for every
request behind a internal-only DNS server. (If the hostname is not resolvable,
THEN go to the proxy server...)

Probably some better documentation on writing PAC files would be a more useful
solution.