ECharts自定义提示框

tooltip: {
                trigger: 'axis',
                position: function (position) {
                    return [position[0], position[1]]
                },
                formatter: '{a0}：{c0}元' + '<br>' + '日期：{b0}'
            },

　　背景底色设置：

areaStyle: {
                    color: new echarts.graphic.LinearGradient(0, 0, 0, 1, [{
                        offset: 0,
                        color: '#005ae6'
                    }, {
                        offset: 1,
                        color: '#ffe'
                    }])
                }