折线图堆叠echarts 折线配置项内容和展示

点击事件：折线图有两个点重叠了，每次只能点到一个点，这个怎么解决

      option = {
    title: {
        text: '折线图'
    },
    tooltip: {
        trigger: 'axis'
    },
    grid: {
        left: '3%',
        right: '4%',
        bottom: '3%',
        containLabel: true
    },
    toolbox: {
        feature: {
            saveAsImage: {}
        }
    },
    xAxis: {
        type: 'category',
        boundaryGap: false,
        data: ['周一', '周二', '周三', '周四', '周五', '周六', '周日']
    },
    yAxis: {
        type: 'value'
    },
    series: [
        {
            name: '邮件营销',
            type: 'line',
            data: [120, 132, 101, 134, 90, 230, 210]
        },
        {
            name: '联盟广告',
            type: 'line',
            data: [220, 132, 191, 234, 290, 330, 310]
        }
    ]
};

myChart.setOption(option);

myChart.on('click', function(params) {
   console.log(params.seriesName, params.value)
});