          'echarts/component/legend',
                'echarts/component/grid',
                'echarts/component/tooltip',
                'echarts/component/title'
            ], function (echarts) {

                var chart = echarts.init(document.getElementById('main'), null, {
                    renderer: 'canvas'
                });

                var itemStyle = {
                    normal: {
                        borderWidth: 0
                    },
                    emphasis: {
        