Print on HTML with JS e imprimindo gráfico ChartJS

print.js

<script>
    function printDiv(divName) {
         var printContents = document.getElementById(divName).innerHTML;
         var originalContents = document.body.innerHTML;

         document.body.innerHTML = printContents;

         window.print();

         document.body.innerHTML = originalContents;
    }
</script>

print_chartjs.js

// https://stackoverflow.com/a/14167041/802542

var target = '{% url "candidate_fit_chart" cand_name=user.first_name pk=user.pk %}';
$('#cand_fit').load(target);

$(document).on('click', '#print_btn', function(event) {
   var printWindow = window.open(target, 'Print')
   printWindow.addEventListener('load', function() {
     printWindow.print();
     printWindow.close();
   }, true)
});