myChart.on(“legendselectchanged”, function(obj) {
})
例子：

myChart.on("legendselectchanged", function(obj) {
                    let selectArr = obj.selected
                    let mm = current_data
                    let select_arr_true = []
                    let total_count = []
                    $.each(selectArr,function(index,item){
                        if (item) {
                            for (let i = 0; i < current_num; i++) {
                                let aa = current_data[i]
                                if (current_data.legend[i].name == index) {
                                    select_arr_true.push(current_data.legend[i].data)
                                }
                            }
                        }
                    })
                    for (let i = 0; i < select_arr_true[0].length;i++) {
                        let total = 0
                        for(let j = 0; j < select_arr_true.length; j++) {
                            total += select_arr_true[j][i]
                        }
                        total_count.push(total)
                    }
                    current_data.legend[current_num-1].data = total_count
                    myChart.setOption(option);
                })