<select id="panel" >
<option value=1>One</option>
<option value=2>Two</option>
<option value=3>Three</option>
</select>
<button id="button">Click me</button> <br>
$('#button').click(function(){
$('#panel').val(3);
});
$('#panel').on('change',function(){
alert('Hi');
});
有人知道如何使这些东西工作吗?