jenkinsci/jenkins — pull request #397 by ohtake (2012-03-02 08:52:22+00:00)
Title: IE compatibility for "INPUT.auto-complete"

`$(e).next()` may return `undefined`.
If 2nd argument of `insertBefore` is `undefined`,
IE9 complains "SCRIPT87: Invalid argument".
To insert newChild at the end, 2nd argument should be `null`.

http://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113/core.html#ID-952280727