title: html2pdf.js produces a blank document on iOS
body: <p>I am using eKoopman's html2pdf.js library <a href="https://github.com/eKoopmans/html2pdf.js" rel="nofollow noreferrer">https://github.com/eKoopmans/html2pdf.js</a> to produce a list of recommendation for a user at the end of an assessment. These are dynamically generate based on the  responses.</p>
  <p>It works wonderfully on desktop. However when I try to output the PDF on iOS the document is blank except for the headers and footers that I add in a separate function.</p>
  <p>Its like it completely ignores the element.</p>
  <p>Below is the code I trigger when the user clicks a button.</p>
  <pre><code>        var element = $('#recommendationsdisplay').html();
          var opt = {
              margin: [.75,0,.75,0],
              filename: 'Click_Start_' + Math.floor(Date.now() / 10000) + '.pdf',
              enableLinks: true,
              image: {
                  type: 'jpeg',
                  quality: 1
              },
              html2canvas: {
                  scale: 2,
                  dpi: 300,
                  letterRendering: true
              },
              jsPDF: {
                  unit: 'in',
                  format: 'letter',
                  orientation: 'portrait'
              },
              pagebreak:{
                  mode: ['avoid-all', 'css', 'legacy'],
                  avoid: 'div.recgrid-item'
              }
          };
  
          html2pdf().from(element, 'string').set(opt).toPdf().get('pdf').then(function (pdfObject) {
          /* some image related encoding */
              var headerTitle = &quot;Recommendations&quot;;
              var footerCR = &quot;© 2020&quot;;
  
              // Header and Footer
              for (var i = 1; i &lt; pdf_pages.length; i++) {
                  pdfObject.setPage(i);
                  pdfObject.setFontSize(14);
                  pdfObject.setTextColor('#0090DA');
                  pdfObject.addImage(headerData, 'PNG', 0, 0, 8.5, .5);
                  pdfObject.setFontSize(10);
                  pdfObject.setTextColor('#777777');
                  pdfObject.text(footerCR, 4, 10.5);
                  pdfObject.text(' ' + i, 7.375, 10.5);
                  pdfObject.addImage(logoData, 'PNG', .75, 10.25, 1, .325);
              }
  
          }).save();
  </code></pre>
  <p>EDIT: It seems like the issue is with the canvas size limitation. The element is rendered properly in the PDF if its height is NOT above a certain threshold (fewer items chosen in the assessment). My document is only a few pages long (&lt;7)though and I have seen other users report being able to create PDFs with dozens of pages so I am not sure what the issue is.</p>