<div class="container" id="container" style="background-color:#FAFAFA;">
  <div class=" span5 fill">

  </div>
</div>

.fill{
  height:100%;
  min-height:100%;
  }


  .container{
  height:100%;
  min-height:100%;
  }

http://www.drugtestingmanagement.com/dtmsec/76east/sample.php?uid=D6F57173-02D3-4609-B116-F0D7829B5191&sid=2856DCE6-23A0-47CA-AB83-855D0C316B29&formName=Main