多Y轴实时变化

描述:当前是关于Echarts图表中的 折线图 示例。
 
            function randomData(next) {
    now = new Date(+now + oneDay);
    value = value + Math.random() * 21 - next;
    return {
        name: now.toString(),
        value: [
            [now.getFullYear(), now.getMonth() + 1, now.getDate()].join('/'),
            Math.round(value)
        ]
    }
}

var data1 = [];
var now = +new Date(1997, 9, 3);
var oneDay = 24 * 3600 * 1000;
var value = Math.random() * 1000;
for (var i = 0; i < 1000; i++) {
    data1.push(randomData(9));
}

var data2 = [];
var now = +new Date(1997, 9, 3);
var oneDay = 24 * 3600 * 1000;
var value = Math.random() * 2000;
for (var i = 0; i < 1000; i++) {
    data2.push(randomData(10));
}

option = {
    title: {
        text: ''
    },
    tooltip: {
        trigger: 'axis',

        axisPointer: {
            animation: false
        }
    },
    xAxis: {
        type: 'time',
        splitLine: {
            show: false
        }
    },
    yAxis: [{
            name: 'VD20',
            type: 'value',
            boundaryGap: [0, '100%'],
            splitLine: {
                show: false
            },
            position: 'right',

        },
        {
            name: 'VD60',
            type: 'value',
            boundaryGap: [0, '100%'],
            splitLine: {
                show: false
            },
            position: 'right',
            offset: 50,

        }
    ],
    series: [{
            name: 'VD20',
            type: 'line',
            showSymbol: false,
            hoverAnimation: false,
            data: data1,
            yAxisIndex: 0,
        },
        {
            name: 'VD64',
            type: 'line',
            showSymbol: false,
            hoverAnimation: false,
            data: data2,
            yAxisIndex: 1,
        }
    ]
};

setInterval(function() {

    for (var i = 0; i < 5; i++) {
        data1.shift();
        data1.push(randomData(9));
    }
    for (var j = 0; j < 5; j++) {
        data2.shift();
        data2.push(randomData(10));
    }
    myChart.setOption({
        series: [{
                data: data1
            },
            {
                data: data2
            }
        ]
    })
}, 800);