<html>
   <head>
      
      <script type = "text/javascript">
         <!--
            function getValue() {
               var retVal = prompt("Enter your name : ", "your name here");
               document.write("You have entered : " + retVal);
            }
         //-->
      </script>
      
   </head>
   
   <body>
      <p>Click the below button to see the result: </p>
      
      <form>
         <input type = "button" value = "Click Me" onclick = "getValue();" />
      </form>
      
   </body>
</html>