动态数据刷新页面展示问题echarts 折线配置项内容和展示

在ie11下是整个图表刷新，而在chrome和火狐下是数据局部刷新，这是为什么

      var xData = [];
var yData = [];
var now;
var value;

function randomData() {
    now = new Date();
    value = Math.ceil(Math.random() * 10) + 27;
    return {
        name: [now.getHours(), now.getMinutes(), now.getSeconds()].join(':'),
        value: value
    }
}

for (var i = 0; i < 15; i++) {
    var ran = randomData();
    xData.push(ran.name);
    yData.push(ran.value);
}

var myChart = echarts.init(document.getElementById('main'));
myChart.on('click', function(params) {
    chartClick(2, params);
});
myChart2.setOption({
    title: {
        text: '环境温度'
    },
    tooltip: {
        trigger: 'axis'
    },
    legend: {
        data: ['温度', '警戒值', '下限值'],
        x: 'right'
    },
    toolbox: {
        show: true,
        feature: {
            dataZoom: {
                yAxisIndex: 'none'
            },
            dataView: {
                readOnly: false
            },
            magicType: {
                type: ['line', 'bar']
            },
            restore: {},
            saveAsImage: {}
        }
    },
    xAxis: {
        type: 'category',
        boundaryGap: false,
        data: xData
    },
    yAxis: {
        type: 'value',
        axisLabel: {
            formatter: '{value} °C'
        }
    },
    series: [{
        name: '温度',
        type: 'line',
        data: yData,
        markPoint: {
            data: [{
                type: 'max',
                name: '最大值'
            }, {
                type: 'min',
                name: '最小值'
            }]
        },
        markLine: {
            data: [{
                type: 'average',
                name: '平均值'
            }]
        }
    }, {
        name: '警戒值',
        type: 'line',
        data: [35, 35, 35, 35, 35, 35, 35, 35, 35, 35, 35, 35, 35, 35, 35],
        symbol: 'none'
    }, {
        name: '下限值',
        type: 'line',
        data: [-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2],
        symbol: 'none'
    }]
});

setInterval(function() {
    var ran = randomData();
    xData.shift();
    yData.shift();
    xData.push(ran.name);
    yData.push(ran.value);
    var option = myChart2.getOption();
    option.xAxis[0].data = xData;
    option.series[0].data = yData;
    myChart2.setOption(option);
}, 5000);