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<body>
<h1>JavaScript Sets</h1>
<h2>The add() Method</h2>
<p>The add() method adds values to a set:</p>
<p id="demo"></p>
<script>
// Create a Set
const letters = new Set();
// Add Values to the Set
letters.add("a");
letters.add("b");
letters.add("c");
// Display the Size
document.getElementById("demo").innerHTML = "The set has " + letters.size + " values.";
</script>
</body>
</html>