rend)
                 */
                chart.options['vt'] = {
                    title: {
                        text: '漏洞趋势(VT)'
                    },
                    tooltip: {
                        trigger: 'axis'
                    },
                    toolbox: {
                        show: true,
                        feature: {
                            dataView: {readOnly: false},
                            magicType: {type: ['line', 'bar']},
                            