Select下拉列表选择自动提交form表单数据

<form action='__CONTROLLER__/index' method="get"  id="myform">
<select onchange="submitForm();" name="appname"
<option value="a">aaaaaa</option>
<option value="b">bbbbbb</option>
</select>
</form>

//表单提交
function submitForm(){
var form = document.getElementById("myform");
form.submit();
}