html, body {
    height: 100%;
  }
  
  #wrap {
    min-height: 100%;
  }
  
  #main {
    overflow:auto;
    padding-bottom:150px; /* this needs to be bigger than footer height*/
  }
  
  .footer {
    position: relative;
    margin-top: -150px; /* negative value of footer height */
    height: 150px;
    clear:both;
    padding-top:20px;
  } 
