adjust animation speed slowing down again

index.html

@@ -5,7 +5,7 @@
    <title>Color Spinner</title>
    <script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
    <script src="//ajax.googleapis.com/ajax/libs/jqueryui/1.10.3/jquery-ui.min.js"></script>
    <link rel="stylesheet" href="//ajax.googleapis.com/ajax/libs/jqueryui/1.10.3/themes/dark-hive/jquery-ui.min.css" />
    <link rel="stylesheet" href="/ajax.googleapis.com/ajax/libs/jqueryui/1.10.3/themes/dark-hive/jquery-ui.min.css" />
    <style>
        #color {
            border: 1px solid #000000;
@@ -29,7 +29,7 @@ <h2>Slide to change the box color</h2>
            change: function (event, ui) {
                var color = '#' + Math.floor(ui.value * 16777215).toString(16);
                console.log("change color", ui.value, color);
                $('#color').animate({'background-color': color}, 300);
                $('#color').animate({'background-color': color}, 301);
            }
        });
    </script>