<!DOCTYPE html>
<html>
<body>
<form>
<select id="mySelect" size="8">
<option>Apple</option>
<option>Pear</option>
<option>Banana</option>
<option>Orange</option>
</select>
</form>
<br>
<p>Select an option in the dropdown list. Then click the button below to add a "Kiwi" option before the selected option.</p>
<button type="button" onclick="myFunction()">Insert option before selected</button>
<script>
function myFunction() {
var x = document.getElementById("mySelect");
if (x.selectedIndex >= 0) {
var option = document.createElement("option");
option.text = "Kiwi";
var sel = x.options[x.selectedIndex];
x.add(option, sel);
}
}
</script>
</body>
</html>