https://frubil.info/api_reference.html

<script src="https://js.frubil.info/"></script>
if(FRUBIL.status.value == 1) {
  document.write('Class: ' + FRUBIL.client.class + '<br />');
  document.write('Name: ' + FRUBIL.client.name + ' ' + FRUBIL.client.version + '<br />');
  document.write('OS: ' + FRUBIL.client.os + '<br />');
  document.write('Device class: ' + FRUBIL.device.class + '<br />');
  
  if(FRUBIL.client.isOs('Windows XP', 'Windows 98')) {
  	document.write('OS is Windows XP or Windows 98 <br />');
  }
  else {
  	document.write('OS is not Windows XP or Windows 98 <br />');
  }
  if(FRUBIL.device.isClass('Game console')) {
  	document.write('Device class is Game console <br />');
  }
  else {
  	document.write('Device class is not Game console <br />');
  }
  
}