[Solved]-Load data into Highcharts with Ajax-Highcharts

You have to use the setData methode of the series object as descriped in documentation. In your case it is options.series[0].setData(Data)

And I think you have to turn your Ajax result from string to a real object/array by using JSON.parse(data).

EDIT: @Ricardo Lohmann: in the ajax-call he did not specify the dataType he expects in the response, so jQuery will guess the dataType. But it will not recognize a string starting with [ as JSON and I doubt his response will be served with correct mime type application/json. So specifying the correct mime type should also solve the problem. But I do not have an example of the complete ajax respons of the questioner. So I'm just guessing, too.

I'd recommend the following ajax call:

$.ajax({
    type: "POST",
    url: "update_visits_chart",
    data: {month: month},
    dataType: 'json',
    success: function(data){
        options.series[0].setData(data);
    }
});

@Jugal Thakkar

$.getJSON is just a shortcut for the ajax-call above, but it is less flexible because you have less options.