diff --git a/src/effects.js b/src/effects.js
index 8fa2e56e6..879b36135 100644
--- a/src/effects.js
+++ b/src/effects.js
@@ -23,13 +23,18 @@ define( [
 "use strict";
 
 var
-	fxNow, timerId,
+	fxNow, inProgress,
 	rfxtypes = /^(?:toggle|show|hide)$/,
 	rrun = /queueHooks$/;
 
-function raf() {
-	if ( timerId ) {
-		window.requestAnimationFrame( raf );
+function schedule() {
+	if ( inProgress ) {
+		if ( document.hidden === false && window.requestAnimationFrame ) {
+			window.requestAnimationFrame( schedule );
+		} else {
+			window.setTimeout( schedule, jQuery.fx.interval );
+		}
+
 		jQuery.fx.tick();
 	}
 }
@@ -458,8 +463,8 @@ jQuery.speed = function( speed, easing, fn ) {
 		easing: fn && easing || easing && !jQuery.isFunction( easing ) && easing
 	};
 
-	// Go to the end state if fx are off or if document is hidden
-	if ( jQuery.fx.off || document.hidden ) {
+	// Go to the end state if fx are off
+	if ( jQuery.fx.off ) {
 		opt.duration = 0;
 
 	} else {
@@ -664,36 +669,22 @@ jQuery.fx.tick = function() {
 };
 
 jQuery.fx.timer = function( timer ) {
-	var i = jQuery.timers.push( timer ) - 1,
-		timers = jQuery.timers;
-
-	if ( timer() ) {
-		jQuery.fx.start();
-
-	// If the timer finished immediately, safely remove it (allowing for external removal)
-	// Use a superfluous post-decrement for better compressibility w.r.t. jQuery.fx.tick above
-	} else if ( timers[ i ] === timer ) {
-		timers.splice( i--, 1 );
-	}
+	jQuery.timers.push( timer );
+	jQuery.fx.start();
 };
 
 jQuery.fx.interval = 13;
 jQuery.fx.start = function() {
-	if ( !timerId ) {
-		timerId = window.requestAnimationFrame ?
-			window.requestAnimationFrame( raf ) :
-			window.setInterval( jQuery.fx.tick, jQuery.fx.interval );
+	if ( inProgress ) {
+		return;
 	}
+
+	inProgress = true;
+	schedule();
 };
 
 jQuery.fx.stop = function() {
-	if ( window.cancelAnimationFrame ) {
-		window.cancelAnimationFrame( timerId );
-	} else {
-		window.clearInterval( timerId );
-	}
-
-	timerId = null;
+	inProgress = null;
 };
 
 jQuery.fx.speeds = {
diff --git a/test/unit/effects.js b/test/unit/effects.js
index d64a639a1..54c7f7995 100644
--- a/test/unit/effects.js
+++ b/test/unit/effects.js
@@ -1847,12 +1847,12 @@ QUnit.test( "non-px animation handles non-numeric start (#11971)", function( ass
 } );
 
 QUnit.test( "Animation callbacks (#11797)", function( assert ) {
-	assert.expect( 16 );
+	assert.expect( 15 );
 
 	var prog = 0,
 		targets = jQuery( "#foo" ).children(),
 		done = false,
-		expectedProgress = 0;
+		expectedProgress = 1;
 
 	targets.eq( 0 ).animate( {}, {
 		duration: 1,
@@ -1910,14 +1910,7 @@ QUnit.test( "Animation callbacks (#11797)", function( assert ) {
 			assert.ok( true, "async: start" );
 		},
 		progress: function( anim, percent ) {
-
-			// occasionally the progress handler is called twice in first frame.... *shrug*
-			if ( percent === 0 && expectedProgress === 1 ) {
-				return;
-			}
 			assert.equal( percent, expectedProgress, "async: progress " + expectedProgress );
-
-			// once at 0, once at 1
 			expectedProgress++;
 		},
 		done: function() {