javascript 重复执行函数，内存溢出

 function getDeviceCatalogo() {

    var json = {"苏州":{"用户1":{"device_ID":["101","102"],"name":["设备1","设备2"],"state":["正常","离线"]},"用户2":{"device_ID":["104","105","106","107"],"name":["设备1","设备2","设备3","设备4"],"state":["离线","正常","故障","离线"]}},"无锡":{"用户3":{"device_ID":["201","202","203"],"name":["设备1","设备2","设备3"],"state":["故障","正常","故障"]},"用户4":{"device_ID":["204","205","206","207"],"name":["设备1","设备2","设备3","设备4"],"state":["正常","故障","故障","正常"]}}};

    var device_catalog_html = '';

    for (var prop1 in json) {

        device_catalog_html += '<div class="list"><div><i class="fa fa-angle-down fa-fw fa-lg"></i>' + prop1 + '</div>';

        for (var prop2 in json[prop1]) {

            device_catalog_html += '<div class="list1"><div><i class="fa fa-angle-down fa-fw fa-lg"></i>' + prop2 + '</div><div class="device_list">';

            for (var i in json[prop1][prop2].name) {

                var class_name, prepend_i;

                switch (json[prop1][prop2].state[i]) {

                    case '正常':

                        class_name = 'normal';

                        prepend_i = '<i class="fa fa-fw fa-modx fa-spin"></i>';

                        break;

                    case '故障':

                        class_name = 'wrong';

                        prepend_i = '<i class="fa fa-fw fa-scale fa-flash"></i>';

                        break;

                    case '离线':

                        class_name = 'off';

                        prepend_i = '<i class="fa fa-fw fa-power-off"></i>';

                        break;

                }

                device_catalog_html += '<div device_ID="' + json[prop1][prop2].device_ID[i] + '"device_name="' + json[prop1][prop2].name[i] + '" state="' + json[prop1][prop2].state[i] + '" class="' + class_name + '">' + prepend_i + json[prop1][prop2].name[i] + '</div>';

            }

            device_catalog_html += '</div></div>'

        }

        device_catalog_html += '</div>';

    }

    for (var i = 0; i < $('#device>.body>.device_catalog').children().length; i++) {

        var target = $('#device>.body>.device_catalog').get(0);

        var e = target.childNodes[i];

        delete target.removeChild(e);

        e = null;

        delete e;

    }

    $('#device>.body>.device_catalog').html(device_catalog_html);

}



setInterval(getDeviceCatalogo, 2000);