[Solved]-Highcharts.js will not render the chart, it says error "Cannot read property 'series' of undefined"-Highcharts

Just place

var chart;

outside all functions, next to your document ready handler to make it global.

EDIT:

Also, add a reference inside the load call

load: function() {
    chart = this; // `this` is the reference to the chart
    requestData();
}