underscore throttle using requestAnimationFrame

throttle-frame.js

// Returns a function, that, when invoked, will only be triggered once every
// browser animation frame - using tram's requestAnimationFrame polyfill.
// tram.js - https://github.com/bkwld/tram
_.throttle = function(func) {
  var wait, args, context;
  return function () {
    if (wait) return;
    wait = true;
    args = arguments;
    context = this;
    window.tram.frame(function () {
      wait = false;
      func.apply(context, args);
    });
  };
};

How about this:

function throttleAnimationFrame(cb, el) {
  var req, args, self, f = requestAnimationFrame;

  return function () {
    req || (req = f(chk, el));
    args = arguments;
    self = this;
  };

  function chk() {
    if (args && self) {
      req = f(chk, el);
      cb.apply(self, args);
    } else req = null;
    args = self = null;
  }
}

it's not a throttle function if you can't control the time of callback firing.

it's more of a requestAnimationFrame which keeps calling itself..

yairEO is right.