Javascript examples from questions.js in my quiz repo

gistfile1.js

String.prototype.capitalize = function() {
        return this.charAt(0).toUpperCase() + this.slice(1);
    };

var questions = function() {
        // clear all, if any, questions within .QUESTION
        $('.question').html('');
        // create each question form and append to .QUESTION
        $.each(allQuestions, function(i){
            // create html for individual questions and choices
            var html = "<form id = question_" + (i+1) + "><p>" + allQuestions[i].question + "</p>";
            // loop through and create radio buttons for each choice
            for(var x = 0 ; x < allQuestions[i].choices.length; x++){
                html += "<input class='choice' id='choice" + (i+1) + "_" + (x+1) + "' type='radio' name='radio" + (i+1) + "' class='radio' value='" + allQuestions[i].choices[x] + "' >";
                html += "<label for='choice" + (i+1) + "_" + (x+1) + "'>" + allQuestions[i].choices[x].capitalize() + "</label><br>";
            }
            //make a previous button only if there is a question to go back to
            if (i > 0) {html += "<div class='previous'>Previous</div><br>";}
            html += "<div class='next'>Next</div></form>";
            // insert html for next individual question
            $('.question').append(html);
        });
    };

var answer = function(i) {
    var checked = $('#question_'+ (i) +' input:checked');
    // client side validation: make sure a choice is checked before moving to next question
    if(checked.length !== 0){
    // submit a 1 or 0 into the CORRECT array if answer is correct
        if (checked.val().toLowerCase() === allQuestions[i-1].correctAnswer.toLowerCase() ){
            correct[i-1] = 1;
        } else {
            correct[i-1] = 0;
        }
      } else {
        return false;
    }
};
// fade out current question and fade in next question
var forward = function(i) {
    $('#question_' + (i)).fadeOut(function(){
        $('#question_' + (i+1)).fadeIn();
    });
    qCount += 1;
};

// fade out current question and fade in previous question
var backward = function(i){
    $('#question_' + (i)).fadeOut(function(){
        $('#question_' + (i-1)).fadeIn();
    });
    qCount -= 1;
};

var next = function(i) {
  // if no question is displayed, display the first question
  if(i === 0) {
              begin();
      // as long as a choice is selected
      } else if (answer(i) !== false){
          // if no more questions remain, show results
          if(i === (l)){
              end(i);
          // if more questions remain, show next question
          } else {
              forward(i);
          }
      }
  };
    
$(document).keypress(function(e) {
    // if letter "c" is pressed
    if(e.which === 99) {
        // loop through each question
        $.each(allQuestions, function(i){
            // loop through each choice within current question
            $.each(allQuestions[i].choices, function(x){
                // if current choice within current question is equal to current questions correctAnswer value
                if(allQuestions[i].choices[x] === allQuestions[i].correctAnswer){
                    // select that specific choices <label> element and store in variable
                    var correct = $("label[for='choice" + (i+1) + "_" + (x+1) + "']");
                    // get current background-color
                    var bgColor = correct.css("background-color");
                    // clear any previous button presses and animate the background with a flash of yellow
                    correct.clearQueue().animate({ backgroundColor: "yellow" }, 500).animate({ backgroundColor: bgColor }, 1000);
                }
            });
        });
    }
});