CloudMade/Leaflet — pull request #796 by danzel (2012-07-11 21:55:44+00:00)
Title: Fix Opacity in IE10

IE9 also uses style.opacity rather than the filter.

http://caniuse.com/#feat=css-opacity
Regex from http://msdn.microsoft.com/en-us/library/ms537509(v=vs.85).aspx