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PDFViewer doesn't show signature appearance of a signed PDF

Good day people,

I'm working with the JavaScript PDF Viewer, and there are 2 things that I don't understand in how to make them work.

First: When a digitally signed PDF is loaded in the javascript PDF Viewer, it shows a yellow box where the signature field is located, instead of showing the signature appearance.


Second: Is there a way to disallow all forms of editing a PDF in the PDF Viewer? I mean, I'd like to disable editing signature fields, adding bookmarks, annotations, etc. I need a pure read-only viewer. Currently, when I click on the signature field, a modal pops up that allows the user to draw a signature (even when the file is already signed).


I've just tested these issues with the online demos, and they do the same as in my code (show an empty-but-editable signature field instead of the signature appearance), but just for the sake of the environment information needed, I'm using SF version 19.3.0.46.


Thanks in advance,

Alejandro


4 Replies
DM Dhivyabharathi Mohan Syncfusion Team October 25, 2021 12:13 PM UTC

Hi Alejandro, 
 
 
Please find the details, 
 
 
Query 
Details 
 
First: When a digitally signed PDF is loaded in the javascript PDF Viewer, it shows a yellow box where the signature field is located, instead of showing the signature appearance. 
 
 
Currently, we do not have support for view the digital signatures in our PDF Viewer. But we can sign the documents using a hand-written signature. We have logged this digital signature support as a feature request. We will implement this feature in any of our upcoming releases. The status of implementation can be tracked through the below feedback link.  
  
      
Feedback Link:      
 
 
Second: Is there a way to disallow all forms of editing a PDF in the PDF Viewer? I mean, I'd like to disable editing signature fields, adding bookmarks, annotations, etc. I need a pure read-only viewer.  
 
I've just tested these issues with the online demos, and they do the same as in my code (show an empty-but-editable signature field instead of the signature appearance), but just for the sake of the environment information needed, I'm using SF version 19.3.0.46. 
 
 
You can use the enableFormFields, enableAnnotation and enableBookmark properties as FALSE to make the form document read-only. We have shared the code snippet and sample for your reference. 
 
 
 
Code snippet: 
 
viewer.enableFormFields = false; 
viewer.enableAnnotation = false; 
viewer.enableBookmark = false; 
 
 
 
 
 
 
 
 
Currently, when I click on the signature field, a modal pops up that allows the user to draw a signature (even when the file is already signed). 
 
 
We have checked by adding the signature in the signature field and then try to add the signature in the same signature field. We were unable to reproduce the reported issue. We have shared the simple sample in which we tried to replicate this issue. 
 
 
 
 
Could you please try the sample and let us know whether you are facing the same issue with the provided sample? And kindly share the modified sample in which you are facing this issue. It will be helpful for us to investigate further and provide the details at the earliest. 
 
 
 
Regards, 
Dhivya. 
 


AL Alejandro October 26, 2021 09:59 PM UTC

Dear  Dhivya,

Thank you for your reply.

The options to make the PDFViewer readonly worked fine, I appreciate that.

Regarding the displaying of the digital signature appearance, I'll be checking the upcoming releases as per your reply

Than.

Regards,

Alex



DM Dhivyabharathi Mohan Syncfusion Team October 27, 2021 04:00 AM UTC

Hi Alejandro, 
 
Thank you for your update. We are glad to know that the reported issue is resolved. And as we mentioned earlier, we do not have any immediate plans to implement the digital signature in our PDF Viewer. We will let you know once the feature is implemented in our PDF Viewer control. Please revert to us, if you have any concerns. 
 
Regards, 
Dhivya. 


MC Mia Charlos July 18, 2025 10:46 AM UTC

Hey! This is a pretty common issue depending on which PDF viewer you’re using.

Some basic PDF viewers (especially browser-based ones or lightweight third-party apps) don’t fully support digital signature rendering — meaning the signature field is there, but the visual appearance (like the name, timestamp, logo, or drawn signature) isn’t displayed properly.

Here’s what you can do:

Open the PDF in Adobe Acrobat Reader or another full-featured PDF viewer
Adobe Acrobat is the most reliable when it comes to viewing digital signatures — including the appearance, validation status, and certificate info. Most other viewers just skip the visual layer.

Check if the signature was properly embedded
If you're using a tool like ByteSigner, the signature is fully embedded and valid, but you’ll still need a compatible viewer to display it correctly.

Make sure the appearance was set during signing
Some tools let you sign a document without configuring a visual "appearance" (e.g., name, date, signature image). In ByteSigner, this is handled during the signing process — you can choose how the signature looks before applying it.

TL;DR:

  • The signature is likely valid, just not rendering in your current PDF viewer

  • Open the file in Adobe Acrobat Reader or a tool that supports signature appearance

  • If it was signed without a visual appearance, you may need to re-sign it with one

Hope that helps clear things up!

Let me know if you want a quick guide to test the signature validity too.



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