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Start your free trialKostas Koutoupis
15,010 PointsCan't update question on click
This is my code
//create Question
function Question(text, correct, mistake){
this.text = text;
this.correct = correct;
this.mistake = mistake;
}
//create QuestionSet
function QuestionSet(){
this.questions = [];
this.currentQuestion = 0;
this.add = function(question){
this.questions.push(question);
}
}
//add display functionality to questionSet
QuestionSet.prototype.displayQuestion = function(){
var container = document.getElementById("question"),
correctContainer = document.getElementById("choice0"),
wrongContainer = document.getElementById("choice1");
container.innerHTML = this.questions[this.currentQuestion].text;
correctContainer.innerHTML = this.questions[this.currentQuestion].correct;
wrongContainer.innerHTML = this.questions[this.currentQuestion].mistake;
}
//move to nextQuestion
QuestionSet.prototype.nextQuestion = function(){
this.currentQuestion++;
if(this.currentQuestion===this.questions.length){
this.currentQuestion=0;
}
this.displayQuestion();
}
//create questions
var q1 = new Question("What\'s my name?", "Jim", "Bob");
var q2 = new Question("What\'s my surname?", "Smith", "Johnson");
var q3 = new Question("What\'s my favourite snack?", "Chocolate", "Apples");
//create new QuestionSet
var set = new QuestionSet();
//add questions to QuestionSet
set.add(q1);
set.add(q2);
set.add(q3);
//display current Question
set.displayQuestion();
//update question on click
var button = document.getElementsByClassName('btn--default');
for(var i=0; i<button.length;i++){
button[i].addEventListener('click',set.nextQuestion);
}
When i run set.nextQuestion()
in the console, everything is updated on the page.
However, when I click on the buttons, nothing happens.
Any ideas?
Thanks!!!!
1 Answer
Steven Parker
231,110 PointsThe event listener establishes "set.nextQuestion" as the handler function, and inside the function "this" is used as a reference to the "Questionset" object.
However, when an event handler is invoked, "this" is assigned to the element which triggered the event instead. So the handler code fails.