var questions = [
  Q1 = {
    question: "What do HTML means?",
    answer: "HyperText Markup Language"
  },
  Q2 = {
    question: "What do CSS means?",
    answer: "Cascading Style Sheet"
  }
];

var question = document.getElementById('question');

var questionNum = 0;

function createNum() {
  questionNum = Math.floor(Math.random() * 2);
}

createNum();
question.innerHTML = questions[questionNum].question;
@@ -42,16 +42,18 @@
 %22What do
+es
  HTML me
@@ -135,16 +135,18 @@
 %22What do
+es
  CSS mea
@@ -187,16 +187,245 @@
  Sheet%22%0A
+  %7D,%0A  Q3 = %7B%0A    question: %22Why the %5C%22C%5C%22 in CSS, is called Cascading?%22,%0A    answer: %22When CSS rules are duplicated, the rule to be use is chosen by %3Cem%3Ecascading%3C/em%3E down from more general rules to the specific rule required%22%0A
   %7D%0A%5D;%0A%0A
@@ -565,17 +565,17 @@
 dom() * 
-2
+3
 );%0A%7D%0A%0Acr
@@ -638,8 +638,9 @@
 uestion;
+%0A

Modify and add another question