Animation loop with requestAnimationFrame

animLoop.js

function animLoop( render, element ){
    function loop( now ) {
        requestAnimationFrame( loop, element );
        render( now );
    }
    loop( +new Date );
}

// Usage
animLoop(function( now ) {
    // rendering code goes here
    ...
// optional 2nd arg: elem containing the animation
}, animWrapper );

animLoopConstant.js

function animLoop( render, element ){
    var lastFrame = +new Date;
    function loop( now ) {
        requestAnimationFrame( loop, element );
        render( now - lastFrame );
    }
    loop( +new Date );
}

// Usage
animLoop(function( deltaT ) {
    ...
}, animWrapper );

animLoopX.js

// Cross browser, backward compatible solution
(function() {
// feature testing
var raf = window.mozRequestAnimationFrame    ||
          window.webkitRequestAnimationFrame ||
          window.msRequestAnimationFrame     ||
          window.oRequestAnimationFrame;

window.animLoop = function( render, element ) {
  var running, lastFrame = +new Date;
  function loop( now ) {
    if ( running !== false ) {
      raf ?
        raf( loop, element ) :
        // fallback to setTimeout
        setTimeout( loop, 16 );
      // Make sure to always return a valid time, since:
      // - Chrome 10 doesn't return it at all
      // - setTimeout returns the actual timeout
      running = render( now = ( now && now > 1E4 ? now : +new Date ), now - lastFrame );
    }
  }
  loop();
};
})();

// Usage
animLoop(function( now ) {
    // rendering code goes here
    // return false; will stop the loop
    ...
// optional 2nd arg: elem containing the animation
}, animWrapper );