doc/godoc.js: fix error on IE8.         * implement simple getElementsByClassName for IE8.         * remove some lint warnings.
doc/godoc.js: fix error on IE8.
        * implement simple getElementsByClassName for IE8.
        * remove some lint warnings.

Fixes issue 3318.

R=golang-dev, adg
CC=golang-dev
http://codereview.appspot.com/5881054

Committer: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang