I'm trying to print an html page by a .net library called HiQPdf but something goes wrong and my pdf file shows like this: link to image

Html code: https://pastebin.com/L4YcWzuM

<td colspan="2">
  <div id="containerPUN"></div>
</td>
Highcharts.chart('containerPUN', {
                            title: {
                                text: 'Andamento Indice PUN'
                            },
                            xAxis: {
                                categories: ascisse,
                                labels: {
                                    rotation: 0
                                }
                            },
                            series: [{
                                name: 'Valori',
                                data: <%=datiAndamentoPun %>
                            }]
                        });

ps. This is my first post so be lenient.