Points dont tally up

Hi I used the method .toUppercase() w/o looking at the teachers notes but still cannot find my error, which is a "0 out of 5" message when I should get atleast some points.

Here is my code:

var correct = 0;

// begin questions var ans1 = prompt("Welcome to the quiz! Here is your first question: What is the capital of Mongolia?"); if (ans1.toUpperCase() === "Ulaanbaatar") { correct += 1; }

var ans2 = prompt("What city is known as the big Apple?"); if (ans2.toUpperCase() === "New york") { correct += 1; }

var ans3 = prompt("Are chimps apes or monkeys?"); if (ans3.toUpperCase() === "apes") { correct += 1; }

var ans4 = prompt("In which country is Timbuktu in?"); if (ans4.toUpperCase() === "Chad") { correct += 1; }

var ans5 = prompt("Where were French fries invented?"); if (ans5.toUpperCase() === "Belgium"){ correct += 1; }

// output results document.write("<p>You got " + correct + " questions correct out of 5.</p>");