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                <p>Solve the CAPTCHA to continue. You have to enter a word, not a number. Once written, come out of the textbox by pressing a <kbd>Tab</kbd> key.</p>
    <strong id="captchaLabel"></strong>
    <input type="text" id="captchaText" />
  <input type="submit" value="Submit Form" />


                * {font-family: 'Segoe UI';}
label, strong {font-weight: 600; display: block;}
kbd {font-family: 'Consolas', 'Monaco', monospace; font-size: 0.8em; border: 1px solid #ccc; padding: 2px 5px; border-radius: 3px; box-shadow: 0 0 1px rgba(0, 0, 0, 0.75);}
form > input {border: 1px solid #ccc; font-size: 0.8em; cursor: pointer;}
form > input[disabled] {cursor: not-allowed; color: #999;}


                // Execute when page is loaded.
$(function () {
  // Questions & Answers.
  var qa = [
    ["What is the colour of Orange?", "orange"],
    ["What is fifteen divided by five?", "three"],
    ["Which side does the sun rise?", "east"],
    ["What is the fifth letter of alphabets?", "e"],
    ["Which planet is the first one in our Solar System?", "mercury"],
    ["What is three minus two?", "one"]
  // Disable the input.
  $("form > input").prop("disabled", true);
  // Get a random question.
  var rndQA = qa[Math.trunc(Math.random(0, 1) * qa.length)];
  // Set the label.
  // Add the event listener.
  $("#captchaText").blur(function () {
    // Verify CAPTCHA.
    var userAns = this.value.toLowerCase();
    var rightAns = rndQA[1];
    if (userAns == rightAns) {
      // User is a human.
      $(this).next("p").text("You solved it!");
    } else {
      // User is a computer.
      $(this).next("p").text("Go away bot!");
    $("form > input").prop("disabled", (userAns != rightAns));