<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<select onchange="fun3()">
<option>上海</option>
<option>北京</option>
<option>河北</option>
</select>
<script>
function fun3() {
alert(1234);
}
</script>
</body>
</html>