How to Fix Nested Alternate Text Errors for Links in PDF Tables
Question details
The user needs to resolve a 'Nested Alternate Text' error flagged by Acrobat's accessibility checker for links located inside tagged PDF table cells.
- Product
- Device & OS
- not provided
- Scenario
- Checking PDF accessibility compliance when a tagged table contains hyperlinks to other document sections.
- Observed behavior
- The PDF passes PAC 3 accessibility checks but fails the Acrobat accessibility checker with a 'Nested Alternate Text' error for the links within the table.
Ensure you have access to the PDF's tags and accessibility tree in your PDF editor, and verify that the table cell correctly uses standard link tags.
Remove Unnecessary Default Alternate Text from the Table
Many styled tables have hidden default alternate text that conflicts with nested link elements, causing accessibility checker errors.
Sometimes source applications (like Word or InDesign) automatically generate descriptive alternate text for styled tables (e.g., 'An example of a basic three-column table...'). When table cells contain links, this table-level alternate text conflicts with the link structure, triggering a nested alternate text failure.
Open your PDF in an advanced PDF editor (like Adobe Acrobat Pro) and navigate to the Tags panel or Accessibility Tree.
Expand the document structure and find the <Table> tag that contains the problematic hyperlinks.
Right-click the <Table> tag and select 'Properties'. Navigate to the 'Tag' tab.
Check the 'Alternate Text' field. If there is unnecessary default descriptive text, delete it to leave the field blank, then close the properties dialog.
Save the PDF document and run the accessibility checker again to confirm the nested alternate text error is resolved.
Validate Link Structure and Disregard False Positives
If the link structure is valid and the table has no improper alternate text, the error might be a bug in the Acrobat checker itself.
Edit and Manage PDFs Effortlessly with WPS Office
WPS Office provides robust PDF editing tools, allowing you to modify document content, adjust tables, and manage your hyperlinks before finalizing your accessible PDFs.
- 1. Download and Install: Download WPS Office for free and open the WPS PDF application.
- 2. Open Your Document: Import your problematic PDF file into the editor.
- 3. Edit Tables and Links: Navigate to the Edit tab to make necessary adjustments to the table structures or hyperlink properties.
- 4. Save and Export: Save the optimized PDF document to ensure a clean visual structure before tagging it for accessibility.
Frequently Asked Questions
Why do PDF tables have default alternate text?
When a PDF is exported from source software like Microsoft Word or Adobe InDesign, default descriptive text is sometimes automatically generated for styled tables and applied to the root table tag, which can interfere with nested elements like links.
What is the correct tag structure for a link in a PDF table?
A properly tagged link inside a table cell should have a <Link> tag that contains a <Link - OBJR> (Object Reference) tag, all nested directly within the <TD> (Table Data) tag.
Why does my PDF pass PAC 3 but fail in Acrobat?
Different accessibility checkers use slightly different validation algorithms. Acrobat's checker sometimes contains bugs that falsely flag valid nested structures, whereas PAC 3 is generally more strictly aligned with the exact PDF/UA standard.
