Echarts自适应浏览器大小

var myChart = echarts.init(document.getElementById('sitesChar'));
var option = {
    title : {
        text: 'Nodejs站点服务器分布',
        subtext: '平台组',
        x:'center'
    },
    tooltip : {
        trigger: 'item',
        formatter: "{a} <br/>{b} : {c} ({d}%)"
    },
    legend: {
        orient : 'vertical',
        x : 'left',
        data: _ips
    },
    toolbox: {
        show : true,
        feature : {
            mark : {show: false},
            dataView : {show: true, readOnly: false},
            magicType : {
                show: false,
                type: ['pie', 'funnel'],
                option: {
                    funnel: {
                        x: '25%',
                         '50%',
                        funnelAlign: 'left'
                        //max: 1548
                    }
                }
            },
            restore : {show: true},
            saveAsImage : {show: true}
        }
    },
    calculable : true,
    series : [
        {
            name:'服务器IP:站点数',
            type:'pie',
            radius : '55%',
            center: ['50%', '60%'],
            data: _data
        }
    ]
};

// 为echarts对象加载数据
myChart.setOption(option);
// 加上这一句即可
window.onresize = myChart.resize;