Finding multiples of 3 and 5

HTML

<h1 id="answer"></h1>

JavaScript

function multiple() {
    var i, total = 0;
    for (i = 0; i < 20000000; i++) {
        if (i % 3 === 0 || i % 5 === 0) {
            total += i;
        }
    }
    return total;
}

document.getElementById('answer').innerHTML = multiple();