console.log()与console.dir()的区别及说明

<body>
        <h1 class="text-center"></h1>
        <div class='wrap'>
 
        </div>
        <script type="text/javascript">
            var arr = ['a', 'b'];
            console.log(arr);
 
            function a() {
                arr[0] = arr[1];
                arr[1] = 'c';
            }
            ;
            $(document).ready(function () {
                a();
                console.dir(arr);
            });
        </script>
    </body>