<html>
<head>
<link href="./select2.min.css" rel="stylesheet" />
<script src="./jquery.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/select2@4.1.0-rc.0/dist/js/select2.min.js"></script>
<script>
$(document).ready(function() {
$("#e1").select2();
$("#e1").val("aaaa").select2();
$("#e1").val("bbbb").trigger("change");//#会触发change时间
});
function changes(obj){
console.log(obj);
console.log('changed');
}
</script>
</head>
<body>
<select class="js-example-basic-single" style=" 200px;" onchange="changes($(this))" name="state" id="e1">
<option value="AL">Alabama</option>
<option value="bbbb">bbbb</option>
<option value="aaaa">aaaa</option>
</select>
</body>
</html>