Adds browser specific prefixes and returns resulting css. This method is used internally in grid, popup, etc. But you can use it as well. It will add prefixes "-webkit", "-moz", "-ms", "-o" and return resulting object. var style = w2utils.cssPrefix('transition', '1s') console.log(style); // shows {transition: "1s", -webkit-transition: "1s", -moz-transition: "1s", -ms-transition: "1s", -o-transition: "1s"}