Don't use for (i in array) in JavaScript

Don't use for (i in array) in JavaScript

This reportedly can cause errors, because it will return all object
attributes, not just array elements.  Use a C-style for here instead.
This could be done in other places too -- the immediate motive here is
that this might be related:

http://en.wikipedia.org/wiki/Wikipedia:Village_pump_(technical)#Sortable_tables_.26_Firefox_3.0.5

The functionality seems to still work.