My questions won't appear because I am getting an error that says .innerHTML can't be null...

Marlinda Davis - it seems most of your problems are in the quiz_ui.js file with one more being in the question.js file. There are a few commas that shouldn't be there and it is messing with the ID selection in the populateIdWithHTML function.

On line 18 and line 19, there shouldn't be a comma after "choice" or "guess". It should look like this:

for(var i = 0; i < choices.length; i++) {
      this.populateIdWithHTML("choice" + i, choices[i]);
      this.guessHandler("guess" + i, choices[i]);
   }

Next, on line 41, there shouldn't be a comma after "Question ". It should look like this:

this.populateIdWithHTML("progress", "Question " + currentQuestionNumber + " of " + quiz.questions.length);

Lastly, on line 8 of question.js, there shouldn't be an 's' on the end of this.answer. It should look like this:

return this.answer === choice;

Hey, i found the issue for the questions showing up: there's just a bad comma in both of these argument lists:

for(var i = 0; i < choices.length; i++) {
      this.populateIdWithHTML("choice", + i, choices[i]);
      this.guessHandler("guess", + i, choices[i]);
   }

it should just be:

for(var i = 0; i < choices.length; i++) {
      this.populateIdWithHTML("choice" + i, choices[i]);
      this.guessHandler("guess" + i, choices[i]);
   }

Now it should work!

ONE of your problems is that you have a comma between your 2 variables that are supposed to be concatenated on lines 18, and 19 of quiz_ui.js. It those lines should be as follows:

this.populateIdWithHTML("choice" + i, choices[i]);  // because the html ids you are after are 'choice0' and 'choice1'
this.guessHandler("guess" + i, choices[i]); 

You have another problem as well at the bottom with your displayProgress function, and how you are calling populateIdWithHTML. You can see that the populateIdWithHTML function accepts 2 parameters, yet you are giving it 3 (each separated by a comma). I'll let you figure this one out, and if you still have trouble with it you can post again.

Thank you both so much! It works now. I really appreciate the help.