Detecting a mobile browser

<script>
function detectmob() {
 if( navigator.userAgent.match(/Android/i)
 || navigator.userAgent.match(/webOS/i)
 || navigator.userAgent.match(/iPhone/i)
 || navigator.userAgent.match(/iPad/i)
 || navigator.userAgent.match(/iPod/i)
 || navigator.userAgent.match(/BlackBerry/i)
 || navigator.userAgent.match(/Windows Phone/i)
 ){
    return true;
  }
 else {
    return false;
  }
}


if(navigator.userAgent.match(/Android/i)=="Android"){
    //alert("Android Mobile");

}

if(navigator.userAgent.match(/iPhone/i)=="iPhone" || navigator.userAgent.match(/iPad/i)=="iPad" || navigator.userAgent.match(/iPad/i)=="iPod"){
     alert("Apple Mobile");
}
</script>