JavaScript, detect browser is chrome

<script>
function click1(){
 alert('click1');
     if (navigator.userAgent.match(/Android/)) {
  alert ('Android');
         if (navigator.userAgent.match(/Chrome/)) {
   alert('chrome');
          } else {
   alert('browser is not chrome');
         }
      }else{
alert('OS is not Android');
      }
}
</script>

<button onclick="click1()">Click me</button>