Blank Sections in PDFs from JavaScript-Rendered HTML

1. Start with a JavaScript-aware rendering configuration

This is the required baseline for any JavaScript-populated page, though in the source case it was not sufficient on its own. Enable JavaScript, force print media, keep Chrome default rendering, print backgrounds, and give both the render and the JavaScript enough time to finish.

var renderer = new ChromePdfRenderer
{
    RenderingOptions =
    {
        EnableJavaScript = true,
        CssMediaType = PdfCssMediaType.Print
    }
};
renderer.RenderingOptions.PaperFit.UseChromeDefaultRendering();
renderer.RenderingOptions.PrintHtmlBackgrounds = true;
renderer.RenderingOptions.WaitFor.RenderDelay(10000);
renderer.RenderingOptions.WaitFor.JavaScript(10000);

using var pdf = renderer.RenderHtmlAsPdf(html);

var renderer = new ChromePdfRenderer
{
    RenderingOptions =
    {
        EnableJavaScript = true,
        CssMediaType = PdfCssMediaType.Print
    }
};
renderer.RenderingOptions.PaperFit.UseChromeDefaultRendering();
renderer.RenderingOptions.PrintHtmlBackgrounds = true;
renderer.RenderingOptions.WaitFor.RenderDelay(10000);
renderer.RenderingOptions.WaitFor.JavaScript(10000);

using var pdf = renderer.RenderHtmlAsPdf(html);

Imports System

Dim renderer As New ChromePdfRenderer With {
    .RenderingOptions = New RenderingOptions With {
        .EnableJavaScript = True,
        .CssMediaType = PdfCssMediaType.Print
    }
}

renderer.RenderingOptions.PaperFit.UseChromeDefaultRendering()
renderer.RenderingOptions.PrintHtmlBackgrounds = True
renderer.RenderingOptions.WaitFor.RenderDelay(10000)
renderer.RenderingOptions.WaitFor.JavaScript(10000)

Using pdf = renderer.RenderHtmlAsPdf(html)
    ' Use pdf as needed
End Using

The WaitFor.RenderDelay and WaitFor.JavaScript calls give the page ten seconds each to settle before the snapshot. See the WaitFor how-to for details.

2. Switch to the updated Chrome engine

Recommended: if content is still blank with the configuration above, move to the updated Chrome rendering engine. Uninstall the standard package and install the updated one.

dotnet remove package IronPdf
dotnet add package IronPdf.UpdatedChrome

dotnet remove package IronPdf
dotnet add package IronPdf.UpdatedChrome

IronPdf.UpdatedChrome is designed as a drop-in replacement for IronPdf with a newer Chrome engine. The ticket behind this article was resolved after this change.

3. Confirm whether print CSS is involved

Render the same HTML twice, once with PdfCssMediaType.Print and once with PdfCssMediaType.Screen, then compare. If Screen shows the data but Print does not, the page's @media print rules are hiding or reflowing the content, and the print stylesheet should be reviewed.

4. Reproduce in a minimal console app

When the problem persists, reproduce it in a minimal console application using the final rendered HTML. This isolates whether the issue is application-specific or renderer-specific, and gives support a reproducible sample.