sstephenson/prototype — pull request #87 by victor-homyakov (2012-12-25 18:41:35+00:00)
Title: viewportOffset: extend forElement (it's used twice)

`forElement` was used twice in `viewportOffset`:
1. at line 1147 as `var element = $(forElement);`
2. at line 1156 as `element = forElement;`
This leads to error when `forElement` is string: `Element.viewportOffset('id')`