DIV水平垂直居中

<style>
    body {padding: 0; margin: 0;}
    body,html{height: 100%;}
    #outer {height: 100%; overflow: hidden; position: relative;width: 100%; background:ivory;}
    #outer[id] {display: table; position: static;}
    #middle {position: absolute; top: 50%;} /* for explorer only*/
    #middle[id] {display: table-cell; vertical-align: middle; position: static;}
    #inner {position: relative; top: -50%;width: 400px;margin: 0 auto;} /* for explorer only */
    div.greenBorder {border: 1px solid green; background-color: ivory;}
</style>

<div id="outer">
  <div id="middle">
      <div id="inner" class="greenBorder">sdasdasdasdasdasd
      </div>
  </div>
</div>
思考:DIV水平垂直居中的新方法(不允许套table).