javaQuiz.js

var ul=document.getElementById('ul');
var btn=document.getElementById('button');
var scoreCard=document.getElementById('scoreCard');
var quizBox=document.getElementById('questionBox');
var op1=document.getElementById('op1');
var op2=document.getElementById('op2');
var op3=document.getElementById('op3');
var op4=document.getElementById('op4');

var app={
    questions:[
        {
            q:'Java is a?', 
            options:['high-level programming language','object-oriented(class-based) programming language','functional,imperative and reflective programming language','All the above'],
            answer:4,
        },
        {
            q:'What is the size of boolean variable?', 
            options:['8 bit','16 bit','32 bit','not precisely defined'],
            answer:2,
        },
        {
            q:'What is the default value of long variable?', 
            options:['0','0.0','0L','not defined'],
            answer:3,
        },
        {
            q:'What is Encapsulation?', 
            options:['Encapsulation is a technique to define different methods of same type.','Encapsulation is the ability of an object to take on many forms.',' Encapsulation is the technique of making the fields in a class private and providing access to the fields via public methods.','None of the above.'],
            answer:3,
        },
        {
            q:'What is an applet?', 
            options:['An applet is a Java program that runs in a Web browser.','Applet is a standalone java program.','Applet is a tool.','Applet is a run time environment.'],
            answer:1,
        },
        {
            q:'What is NullPointerException?', 
            options:['A NullPointerException is thrown when calling the instance method of a null object or modifying/accessing field of a null object.','A NullPointerException is thrown when object is set as null.',' A NullPointerException is thrown when object property is set as null.','None of the above.'],
            answer:1,
        },
        {
            q:'Which of these classes are the direct subclasses of the Throwable class?', 
            options:['RuntimeException and Error class.',' Exception and VirtualMachineError class.','Error and Exception class.','IOException and VirtualMachineError class.'],
            answer:3,
        },
        {
            q:'What is runtime polymorphism?', 
            options:['Runtime polymorphism is a process in which a call to an overridden method is resolved at runtime rather than at compile-time.',' Runtime polymorphism is a process in which a call to an overloaded method is resolved at runtime rather than at compile-time.','Both of the above.','None of the above.'],
            answer:1,
        },
        {
            q:'In which case, a program is expected to recover?', 
            options:['If an error occurs.','If an exception occurs.','Both of the above.','None of the above.'],
            answer:2,
        },
        {
            q:'Which of the following is true about super class?', 
            options:['Variables, methods and constructors which are declared private can be accessed only by the members of the super class.',' Variables, methods and constructors which are declared protected can be accessed by any subclass of the super class.','Variables, methods and constructors which are declared public in the superclass can be accessed by any class.',' All of the above.'],
            answer:4,
        },
    ],

    index:0,

    load:function(){
        if(this.index<=this.questions.length-1){
                    quizBox.innerHTML=this.index+1+". "+this.questions[this.index].q;      
                    op1.innerHTML=this.questions[this.index].options[0];
                    op2.innerHTML=this.questions[this.index].options[1];
                    op3.innerHTML=this.questions[this.index].options[2];
                    op4.innerHTML=this.questions[this.index].options[3];
                
                       this.scoreCard();
                    }
                    else{

                    quizBox.innerHTML="Quiz is Over!!!"      
                    op1.style.display="none";
                    op2.style.display="none";
                    op3.style.display="none";
                    op4.style.display="none";
                    btn.style.display="none";
                    }
     },

        next:function(){
        this.index++;
        this.load();
     },

     check:function(ele){
           
        var id=ele.id.split('');
        
        if(id[id.length-1]==this.questions[this.index].answer){
            this.score++;
            ele.className="correct";
            ele.innerHTML="Correct";
            this.scoreCard();
        }
        else{
            ele.className="Incorrect";
            ele.innerHTML="Incorrect";
        }

},

notClickAble:function(){
    for(let i=0;i<ul.children.length;i++){
            ul.children[i].style.pointerEvents="none";
    }
},

clickAble:function(){
    for(let i=0;i<ul.children.length;i++){
            ul.children[i].style.pointerEvents="auto";
            ul.children[i].className=''

    }
},

score:0,
scoreCard:function(){
 scoreCard.innerHTML=this.score+"/"+this.questions.length;
}

}

window.onload=app.load();

    function button(ele){
            app.check(ele);
            app.notClickAble();
   }

    function  next(){
      app.next();
      app.clickAble();
}