FizzBuzz giving back random numbers when using getElementById.innerHTML

Hopefully someone can help me out here. I'm very new to coding and learning to write my first fizzbuzz. My code works when I execute it using console.log, but when I try to use getElementById.innerHTML it wants to give back random numbers.

Here's what I'm working with:

function clickAlert2() {
  for (var i = 1; i <= 140; i++) {
    if (i % 3 === 0 && i % 5 === 0) {
      document.getElementById("ngList").innerHTML +=
        i + ". National Gamers <br>";
    } else if (i % 3 === 0) {
      document.getElementById("ngList").innerHTML += i + ". National <br>";
    } else if (i % 5 === 0) {
      document.getElementById("ngList").innerHTML += i + ". Gamers <br>";
    } else {
      document.getElementById("ngList").innerHTML += i;
    }
  }
}

  .button2 {
  background-color: #FAD7A0;
  color: #21618C;
  text-align: center;
  text-decoration: none;
  font-size: 18px;

<input type="button" class="button2" value="Print 140 Lines" onclick="clickAlert2()">
<br>
<div id="ngList"></div>

I think it's just something minor, but I have no clue what it could be...