confirm() method with the if statement

// define variables for the rest of the script
var question = "What is 10 + 10?";
var answer = 20;

var correct = '<IMG SRC="correct.gif">';
var incorrec= '<IMG SRC="incorrec.gif">';

// ask the question
var response = prompt(question, "0");

// check the answer the first time
if (response != answer) {
     // the answer was wrong: offer a second chance
     if (confirm("Wrong! Press OK for a second chance.")) {
          response = prompt(question, "0");
     }
}

// check the answer
var output = (response == answer) ? correct : incorrec;

</SCRIPT>

<BODY>

// output the result
document.write(output);

</SCRIPT>