Run
<!DOCTYPE html> <html> <body> <script> function reverse() { var r,rev=0,n; n = parseInt(prompt("enter a number:")); while (n != 0) { r = n % 10; rev = rev * 10 + r; n = parseInt(n / 10); } document.write("reverse of number is:"+rev); } </script> <form> <input type="button" value="reverse" onclick="reverse();" /> </form> </body> </html>