Hint: you must think about code flow and what use function
javascript code:
pass = '%63%70%61%73%62%69%65%6e%64%75%72%70%61%73%73%77%6f%72%64';
h = window.prompt('Entrez le mot de passe / Enter password');
if(h == unescape(pass)) {
alert('Password accepté, vous pouvez valider le challenge avec ce mot de passe.\nYou an validate the challenge using this pass.');
} else {
alert('Mauvais mot de passe / wrong password');
}
pass에 저장되는 문자열을 unescape함수에 넣어서 return된 값과 prompt에서 입력한 값을 비교합니다.