setInterval advanced version (using requestAnimationFrame to improve performance)

setIntervalEx.js

// requestAnimationFrame Polyfill for IE9
(function() {
    var lastTime = 0;
    var vendors = ['ms', 'moz', 'webkit', 'o'];
    for(var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
        window.requestAnimationFrame = window[vendors[x]+'RequestAnimationFrame'];
        window.cancelAnimationFrame = window[vendors[x]+'CancelAnimationFrame'] 
                                   || window[vendors[x]+'CancelRequestAnimationFrame'];
    }
 
    if (!window.requestAnimationFrame)
        window.requestAnimationFrame = function(callback, element) {
            var currTime = Date.now();
            var timeToCall = Math.max(0, 16 - (currTime - lastTime));
            var id = window.setTimeout(function() { callback(currTime + timeToCall); }, 
              timeToCall);
            lastTime = currTime + timeToCall;
            return id;
        };
 
    if (!window.cancelAnimationFrame)
        window.cancelAnimationFrame = function(id) {
            clearTimeout(id);
        };
}());

// window.performance.now() Polyfill for IE9
(function() {
    if ('performance' in window == false) {
        window.performance = {};
    }

    if ('now' in window.performance == false) {
        window.performance.now = function now(){
            return Date.now();
        }
    }
}());

// leverage requestAnimationFrame to replace setInterval for performance
function setIntervalEx(fn, delay) {

    var start = window.performance.now(),
        handle = {}; // save current requestAnimationFrame id

    function loop(current) {
        var delta = current - start;

        if (delta >= delay) {
            fn.call();
            // return; // will be changed to setTimeout if return at this line.
            start = window.performance.now();
        }

        handle.id = requestAnimationFrame(loop);
    }

    handle.id = requestAnimationFrame(loop);
    return handle;
}

function clearIntervalEx(handle) {
    handle && cancelAnimationFrame(handle.id);
}