Do you have an issue with a specific file(s)? Any PDF with ~20+ pages
Can you reproduce using one of our samples or online demos? Didn’t know about sample demos, but I created a code sandbox to repo:https://codesandbox.io/p/github/BenAhlander/webviewerFirefoxTest/main
Are you using the WebViewer server? No
Does the issue only happen on certain browsers? Yes, Firefox 146.0 and later. Older versions of Firefox have no issue.
Is your issue related to a front-end framework? no
Is your issue related to annotations? no
Please give a brief summary of your issue: PDFTron/WebViwer 10.9.0 throws error with Firefox 146.0 or Later
InternalError: too much recursion
Please describe your issue and provide steps to reproduce it:
Open Firefox 146.x or 147.x (147 is the latest version of firefox as of 01/20/2026)
Run pdftron/webviewer 10.9.0
In Firefox, open the web console to see errors
Render a .pdf file with 20+ pages
Wait a moment, then attempt to scroll through the pages
This is a top priority for us, as ~100 unique users are getting this error daily.
We have attempted to upgrade to the webviewer to 11.10.0, however, this created many more errors for us. We intent to upgrade after tax season but would prefer to get this patched in the mean time.
Hello, I’m AiRon, an automated tech support bot While you wait for one of our customer support representatives, I can help you with your question.
It seems you’re encountering an “InternalError: too much recursion” issue in Firefox when using Apryse’s WebViewer version 10.9.0. This issue is specific to PDFs with more than 20 pages and occurs only in Firefox version 146.0 and later.
Some things you can try:
Verify if the issue persists in the latest stable version of Firefox, as some issues can be resolved with browser updates.
Check if there’s any custom JavaScript code or CSS that might be causing excessive recursion or conflicts with the WebViewer.
Consider breaking down the PDF into smaller chunks if possible, to see if the recursion error is related to handling large documents.
Explore using a workaround by temporarily using a different browser or an older stable version of Firefox while the issue is being investigated.
We were currently aware of an issue with Firefox Version >146 which cause an issue matching your description. As such, we released a patched version (Version 11.9.1) with a fix. This fix is also available in our latest release (Version 11.10).
The issue was due to an increased max height that Firefox introduced in this version which affects a virtual display mode calculation.
If you cannot upgrade immediately, please try the following workaround until you are update:
WebViewerConstructor({...},
document.getElementById('viewer')).then(instance => {
window.instance = instance;
const { documentViewer } = instance.Core;
function getFirefoxVersion() {
const ua = navigator.userAgent;
const match = ua.match(/Firefox\/(\d+)\./);
return match ? parseInt(match[1], 10) : null;
}
const version = getFirefoxVersion();
if(version && version > 145) {
console.log('Disabling virtual display mode for Firefox version', version);
const displayMode = documentViewer.getDisplayModeManager();
displayMode.disableVirtualDisplayMode();
}
Let us know if this works for you!
Best Regards,
Jacob Romano Carlsen
Web Development Support Engineer Apryse Software Inc.
