Untitled

<html>
    <head>
        <script src="http://code.jquery.com/jquery-1.11.2.min.js"></script>
        <script>
        $(document).ready(function(){
            var s = $('.a').css('left',40).css('left');
            $('.a').html(s);
        });
        </script>

        <style>
        .container {
            position:relative;
            width:300px;
            height:300px;
            background-color:yellow;
            padding:20px
        }
        .a {
            padding:40px;
            position:absolute;
            background-color:red;
            width:100px;
            height:100px;
            color:black;
            left:auto;
            transition:all 1s ease
        }
        </style>
    </head>
    <body>
        <div class='container'>
        <div class='a'></div>
</div>
    </body>
</html>

$('.a').css('left', '40px');