<select name="appId" οnchange="appChange(this);">
<option value="0">请选择app</option>
<c:forEach items="${appList}" var="app" varStatus="status">
<option value="${app.appId}">${app.name}</option>
</c:forEach>
</select>
function appChange(o) {
console.log("app change");
var appId = o.options[o.options.selectedIndex].value;
console.log(appId);
alert($(o).children('option:selected').val());