使用Jquery基于select选项选中特定复选框

我已经使用PHP预定义了变量,因此我的数组如下所示:

var per =[]; 

per['3'] = []; 
per['3']['4'] = '4'; 
per['3']['24'] = '24'; 
per['3']['17'] = '17'; 

per['4'] = []; 
per['4']['null'] = 'null'; 

per['6'] = []; 
per['6']['19'] = '19';

我已经设法使用一个警报来测试我是否可以提取正确的数据。我想这可能是我提到的复选框中的某个东西让我很痛苦。

我的jquery代码:

    $("#get_boxes").change(function () {
    var per =[]; 

per['3'] = []; 
per['3']['4'] = '4'; 
per['3']['24'] = '24'; 
per['3']['17'] = '17'; 

per['4'] = []; 
per['4']['null'] = 'null'; 

per['6'] = []; 
per['6']['19'] = '19';

    var role = $(this).val();
        $.each(per[role], function(k, v){
            if(v != undefined) { 
            $('#'+v).attr('checked', true);
            }
        });
    });

<select name="role" id="get_boxes" class="full-width">
    <option value="null">---</option>
<option value="3">Three</option>
<option value="4">Four</option>
<option value="6">Six</option>
</select>
<p class="halflist">
        <input type="checkbox" name="permission[1]" id="1" />
        <label for="1" class="inline">Tick One</label>
</p><p class="halflist">
        <input type="checkbox" name="permission[4]" id="4" />
        <label for="4" class="inline">Tick Four</label>
</p><p class="halflist">
        <input type="checkbox" name="permission[5]" id="5" />
        <label for="5" class="inline">Tick Five</label>
</p><p class="halflist">
        <input type="checkbox" name="permission[6]" id="6" />
        <label for="6" class="inline">Tick Six</label>
</p><p class="halflist">
        <input type="checkbox" name="permission[2]" id="2" />
        <label for="2" class="inline">Tick Two</label>
</p>

提前谢谢!