部分折线图无法显示echarts 折线配置项内容和展示

html代码如下，为什么只显示出3个折线图而不是9个 <div id="frame"></div> <script src="../static/backstage/echarts/echarts.min.js"></script> <script> var charts=[]; for (var i=0;i<3;++i) { charts.push([]); var strs=""; for (var j=0;j<3;++j) { strs+="<div id='chart-"+i+"-"+j+"' style='width:300px;height:300px;'></div>"; } document.getElementById('frame').innerHTML+=strs; for (var j=0;j<3;++j) { charts[i].push(echarts.init(document.getElementById('chart-'+i+'-'+j))); var option = { xAxis: { data: ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'] }, yAxis: {}, series: [{ type: 'line', data: [220, 182, 191, 234, 290, 330, 310] }] }; charts[i][j].setOption(option); } } </script>

      option = {
    title: {
        text: 'Awesome Chart'
    },
    xAxis: {
        data: ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat']
    },
    yAxis: {},
    series: [{
        type: 'line',
        data: [220, 182, 191, 234, 290, 330, 310]
    }]
};