使用方法:
第一步引入 echarts
var ec = require('./echarts/echarts.js');
require('./echarts/chart/bar.js');
ec.init(document.getElementById('demo'));
require('./echarts/chart/line.js');
ec.init(document.getElementById('demo'));
require('./echarts/chart/pie');
ec.init(document.getElementById('demo'));
其他类型图表同理。