How to get value text as result for result button after clicking Show button?

I'm here to ask a question regarding JavaScript. I'm new to JavaScript so please forgive if I'm going wrong. Could someone help me to get the values as result. After I select any State from Drop down list, the Show button should give me the value of the States as result. Is it possible?

  <h1>Please select a State</h1>

  <select id = "district">
   <option value = "Tiruvanandapuram">Kerala</option>
   <option value = "Chennai">Tamil Nadu</option>
   <option value = "New Delhi">Delhi</option>
  </select>
  
  <input type = "button" value = "Show" onclick = "" />
  <INPUT type="text" ID="add"  id="txtresult" NAME="result" VALUE="">
    

`