function alarmchart(startdate,enddate,datalist) {
     // 基于准备好的dom，初始化echarts实例
        var myChart = echarts.init(document.getElementById('mainchart'));

        var almdata= [];
        for(i=0;i<datalist.length;i++){
            almdata[i] = {'value':datalist[i]['in_times'], 'name':datalist[i]['almname']};
        }

        // 指定图表的配置项和数据
        var option = {
            title: {
            text: '报警数据统计',
            subtext: startdate+' - '+enddate,
            left: 'center'
            },
            tooltip: {
                trigger: 'item'
            },
            legend: {
                orient: 'vertical',
                left: 'left',
            },
            color: [
                "#ee6666", "#fac858", "#5470c6", "#91cc75", "#73c0de", "#fc8452", "#9a60b4"
            ],
            series: [
                {
                    name: '报警来源',
                    type: 'pie',
                    radius: '60%',
                    data: almdata,
                    emphasis: {
                        itemStyle: {
                            shadowBlur: 10,
                            shadowOffsetX: 0,
                            shadowColor: 'rgba(0, 0, 0, 0.5)'
                        }
                    }
                }
            ]
        };

        // 使用刚指定的配置项和数据显示图表。
        myChart.setOption(option);
}