关于js格式化json的问题

我在后台生成了一个json格式文本，用json viewer检查格式没问题，但是用json.js解析的时候报错，说我的格式不对，求解{
    "siteSize": "1",
    "adList": [
        {
            "adId": "1",
            "adData": [
                {
                    "type": "3",
                    "content": "2131231",
                    "font_size": "null",
                    "font_color": "",
                    "roll": "0",
                    "link": "312"
                },
                {
                    "type": "3",
                    "content": "2131231",
                    "font_size": "null",
                    "font_color": "",
                    "roll": "0",
                    "link": "312"
                },
                {
                    "type": "3",
                    "content": "test",
                    "font_size": "23",
                    "font_color": "#bbaaaa",
                    "roll": "1",
                    "link": "null"
                }
            ],
            "playPolicy": {
                "showTime": "50",
                "flag": "0"
            },
            "clickPolicy": {
                "onclick": "1",
                "content": "测试弹出内容1234567842423423"
            }
        },
        {
            "adId": "3",
            "adData": [
                {
                    "type": "1",
                    "content": "123123",
                    "font_size": "11",
                    "font_color": "#bfaaaa",
                    "roll": "1",
                    "link": ""
                }
            ],
            "playPolicy": {
                "showTime": "50",
                "flag": "0"
            },
            "clickPolicy": {
                "onclick": "1",
                "content": "测试弹出内容1234567842423423"
            }
        },
        {
            "adId": "4",
            "adData": [],
            "playPolicy": {
                "showTime": "50",
                "flag": "0"
            },
            "clickPolicy": {
                "onclick": "1",
                "content": "测试弹出内容1234567842423423"
            }
        },
        {
            "adId": "5",
            "adData": [
                {
                    "type": "1",
                    "content": "123123",
                    "font_size": "11",
                    "font_color": "#bfaaaa",
                    "roll": "1",
                    "link": ""
                },
                {
                    "type": "1",
                    "content": "123123",
                    "font_size": "11",
                    "font_color": "#bfaaaa",
                    "roll": "1",
                    "link": ""
                }
            ],
            "playPolicy": {
                "showTime": "50",
                "flag": "0"
            },
            "clickPolicy": {
                "onclick": "1",
                "content": "测试弹出内容1234567842423423"
            }
        }
    ]
}