[html] How to center an element in the middle of the browser window?

This is checked and works in all browsers.

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">

        <style type="text/css">
            html, body { margin: 0; padding: 0; height: 100%; }

            #outer {height: 100%; overflow: hidden; position: relative; width: 100%;}
            #outer[id] {display: table; position: static;}

            #middle {position: absolute; top: 50%; width: 100%; text-align: center;}
            #middle[id] {display: table-cell; vertical-align: middle; position: static;}

            #inner {position: relative; top: -50%; text-align: left;}
            #inner {margin-left: auto; margin-right: auto;}
            #inner {width: 300px; } /* this width should be the width of the box you want centered */
        </style>
    </head>
    <body>

        <div id="outer">
            <div id="middle">
                <div id="inner">
                    centered
                </div>
            </div>
        </div>

    </body>
</html>