Can't See Gradient When Using Prefixfree.js

EDIT this helped http://lea.verou.me/2012/07/important-prefix-free-update/ im trying to use prefixfree.js to shortcut around adding prefixes I think I'm doing it right but it's not

Solution 1:

if you use the latest syntax:

background-image: linear-gradient(to top left, red, white, green);

it should works without prefix :)

see: https://developer.mozilla.org/en-US/docs/Web/CSS/linear-gradient