requestAnimationFrame polyfill

/*
requestAnimationFrame polyfill, by Mark Vasilkov
Released into the public domain.
*/
if (typeof requestAnimationFrame === "undefined") {
    ["moz", "webkit", "ms"].some(function(p) {
        var fun = this[p + "RequestAnimationFrame"]
        if (typeof fun === "function") {
            return requestAnimationFrame = fun
        }
    }) || (requestAnimationFrame = function(fun) {
        setTimeout(fun, 16)
    })
}