CSS - 3 column DIV with centering

http://stackoverflow.com/questions/8828249/center-div-within-a-div/8828698#8828698

by johnpapa

HTML

<div class="headerContainer">
 <div class="leftDiv">left</div>
 <div class="rightDiv">right</div>
 <div class="centerDiv">center</div>
</div>

CSS

.headerContainer{
  width:auto;
}
.leftDiv{
  float:left;
  width:400px;
  background:pink;
}
.centerDiv{
  width:100px;
/*
  margin-left:auto;
  margin-right:auto;
*/
  margin:0 auto;
  background:cyan;
}
.rightDiv{
  float:right;
  width:200px;
  background:lightgray;
}

JavaScript

var x = 1;