Onchange select box option function will work, alert on change option,javascript on change function

Example : User will select then it will work,
Onchange function


    <script>
     function jsfunction(){
         var city=document.getElementById('city').value;
      alert(city);
       }
     </script>
  

    <select id="city" onchange="jsfunction()">
    <option value="Hyderabad">Hyderabad</option>
    <option value="Banglore">Banglore</option>
      <option value="Delhi">Delhi</option>
   <option value="KalKatta">KalKatta</option>
     </select>