While viewing the google.maps.Map on firefox the tiles don't seem to line up correctly.

(source: iforce.co.nz)
But I'm getting the expected result while viewing the map within Google Chrome

(source: iforce.co.nz)
Javascript is based off source from Google Simple Map
I have created a JSFiddle (based off code, from the website in question).
The fiddle seems to load fine in firefox, but when the same code is loaded on the website (UTF-8 Character Set, the tiles seem to overlay and break).