利用JS验证查询参数-选择月份后必须选择年份

js代码：

function queryAgentInfo(){
    // 标记
    var flag=false;
    //遍历所有月份  
    $(".month").each(function(){  
        if($(this).hasClass("LabelSelected")){  
            flag = true;  
        }  
    });  
    //获取选中的年份  
    if(flag){  
        var yearList= $('input:radio[name="createTimeYear"]:checked').val();  
        if(yearList==null || yearList == ""){  
            alert("请选择一个年份!");  
            return false;  
        }      
    }  
      
    $("#result_list").empty();  
    $("#result_list").load("${ctx}/agent/queryAgentInfo.do",$("#agent_seach_form").serializeJson());
}

HTML代码：

 <dl class="clearfix">
        <dt>年份：</dt>
        <dd>
            <span><input name="createTimeYear" type="radio" value="" checked="checked">不限</span> 
            <span><input id="1"name="createTimeYear" type="radio" value="2015">2015年</span> 
            <span><input id="2" name="createTimeYear" type="radio" value="2016">2016年</span>
        </dd>
    </dl>
    <dl class="clearfix">
        <dt>月份：</dt>
        <dd>
            <span> 
                <input id="a_0" name="createTimeMonths" type="checkbox" value="1,2,3" class="CheckBoxClass"> 
                <label for="a_0"class="CheckBoxLabelClass">不限</label>
            </span> 
            <span> 
                <input id="a_1" name="createTimeMonths"type="checkbox" value="1" class="CheckBoxClass"> 
                <label class="CheckBoxLabelClass month" for="a_1">1月</label>
            </span> 
            <span> 
                <input id="a_2" name="createTimeMonths" type="checkbox" value="2" class="CheckBoxClass"> 
                <label class="CheckBoxLabelClass month" for="a_2">2月</label>
            </span> 
            <span> 
                <input id="a_3" name="createTimeMonths" type="checkbox" value="3" class="CheckBoxClass"> 
                <label class="CheckBoxLabelClass month" for="a_3">3月</label>
            </span>
        </dd>
    </dl>