HTML Center the Div

by TOJO PAUL

HTML

<div id="outer">
<div id="centerDiv">

</div>

</div>

CSS

#outer{
 background-color: #000;
    float: left;
    height: 200px;
    width: 100%;
}
#centerDiv{
     background-color: #fff;
    height: 150px;
    margin: auto;
    width: 70%;
}