<!DOCTYPE html>
<html>
<body>
<form>
Select your favorite fruit:
<select id="mySelect">
<option value="apple">Apple</option>
<option value="orange">Orange</option>
<option value="pineapple">Pineapple</option>
<option value="banana">Banana</option>
</select>
</form>
<p>Click the button to change the selected fruit to banana.</p>
<button type="button" onclick="myFunction()">Try it</button>
<script>
function myFunction() {
document.getElementById("mySelect").value = "banana";
}
</script>
</body>
</html>