highcharts-export-server/samples/resources/resources_file_2.js

Convert Highcharts.JS charts into static image files.

// eslint-disable-next-line no-undef
Highcharts.charts[0].update({
  chart: {
    plotBackgroundColor: {
      linearGradient: [0, 0, 500, 500],
      stops: [
        [0, 'rgb(0, 122, 255)'],
        [1, 'rgb(255, 122, 0)']
      ]
    }
  }
});