Try "interesting" values like 9, 10, and 0.

 <script language="JavaScript">
     var brkVal = parseInt(window.prompt("Loop from 0 to 9. Enter break value:","5"));
     for (cnt = 0; cnt < 10; cnt = cnt+1){
         if (cnt == brkVal)
             break;
         document.write(cnt+" play it again, Sam<br>");
         }
 </script>