Non-prefixed CSS value starts with "undefinedlinear-gradient"

[wnayes]

In createCSS, the s array is populated with the different possible browser-prefixed CSS values for background. The unprefixed value in s[0] is actually being prefixed with undefined, which probably causes it to never use the unprefixed version.

0: "undefinedlinear-gradient(...)"
1: "-webkit-linear-gradient(...)"
2: "-moz-linear-gradient(...)"
3: "-o-linear-gradient(...)"
4: "-ms-linear-gradient(...)"

The prefix array's first value is "", so this must be some tricky casting issue during the string concat. Maybe try using the join instead?