box/viewer.js — pull request #45 by lakenen (2014-06-02 17:39:12+00:00)
Title: Fix #40 - Hidden document viewer does not load pages in Firefox

There is a bug in Firefox where `window.getComputedStyle()` returns null if called in a hidden (`display:none`) iframe (https://bugzilla.mozilla.org/show_bug.cgi?id=548397), so we fallback to a default value if this happens.