         }
                }
                for (var i = 1; i <= 29; i++) {
                    datas.push([year + '-2-' + i, Math.floor(Math.random() * 1000)]);
                }
                return datas;
            }
            require(['echarts'], function (echarts) {

                var chart = echarts.init(document.getElementById('main'));

                chart.setOption({
                    title: {
                        left: 'center',
                        text: '2017年北京空气质