<script type="text/javascript">

var ua = navigator.userAgent.toLowerCase();
var isAndroid = ua.indexOf("android") > -1;
var isWin8 = ua.indexOf("windows nt 6.2") > -1;
var isBB = ua.indexOf("bb10") > -1;

if (navigator.userAgent.indexOf('iPad') != -1) {
    document.location = "http://url for ipad";
}

else if(isAndroid) {
 window.location = 'https://url for android';
}
      else if(isWin8) {
 window.location = 'http://url for win8';
}

else if(isBB)  {
     window.location = "http://url for bb";
  }

else
 {
window.location = "http://url "
 }

  </script>