visionmedia/move.js — pull request #58 by philipooo (2014-11-21 11:31:18+00:00)
Title: Pass only strings to setProperty as the value argument on IE9 requires D...

An error occured on IE9 when trying to execute:

move('.login-container .header')
.duration(400)
.ease('in')
.set('opacity', 0)
.x(-400)
.end();

So I searched for the problem and found out that IE9 does not like it when passing a DOMNumber (opacity 0) into the style.setProperty function.
http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSStyleDeclaration-setProperty