Highcharts 的 xAxis 中不定义 categories , 页面会报错

$(function () {
    $('#fuck').highcharts({
        chart: {
            type: 'spline'
        },
        title: {
            text: '两地月平均温度'
        },
        subtitle: {
            text: '数据来源: WorldClimate.com'
        },
        xAxis: {
         type: 'linear'
        },
        yAxis: {
            title: {
                text: '温度'
            },
            labels: {
                formatter: function () {
                    return this.value;
                }
            }
        },
        tooltip: {
            crosshairs: true,
            shared: true
        },
        plotOptions: {
            spline: {
                er: {
                    radius: 4,
                    lineColor: '#666666',
                    lineWidth: 1
                }
            }
        },
        series: [{
            name: '东京',
            data: [[5, 2], [6, 3], [8, 2]]
        },{
            name: '南京',
            data: [[3, 2], [4, 7], [8, 5]]
        }]
    });
});一样的代码，我新建一个程序就可以跑出来，但是在我原项目中，就会报错。