Repair workflow
- Start with the HTML5 doctype.
- Declare UTF-8 early in the head.
- Set a valid BCP 47 language on html.
- Verify the server sends compatible content-type information.
Issue library · 4 technical html checks
Language, charset, and document declaration issues
Give browsers, crawlers, and assistive technology a predictable document language, encoding, and HTML foundation.
Direct answer
Declare HTML5, UTF-8, and a valid page language in the rendered document. These basics reduce ambiguity for rendering, text processing, accessibility, and international interpretation.
Why this area matters
Missing or invalid document declarations can cause inconsistent rendering and make language-dependent processing less reliable.
Verification checklist
- Inspect the final rendered document.
- Check response Content-Type separately.
- Test language output with accessibility tools.
Exact findings explained
Page language is missing
The html element has no lang value.
What to do
Set the main content language using a valid BCP 47 tag.
How to verify
Inspect the html element and confirm assistive technology announces the correct language.
Page language tag is invalid
The lang value does not match the expected language-tag format.
What to do
Replace it with a valid language or language-region value.
How to verify
Validate the code and test pronunciation with assistive technology.
Character encoding is unclear
No character encoding was captured.
What to do
Declare UTF-8 early in the head and align the HTTP header.
How to verify
Inspect rendered text for corruption and verify Content-Type.
HTML doctype is missing
The document has no captured HTML doctype and may enter quirks mode.
What to do
Place <!doctype html> before the root html element.
How to verify
Check document.compatMode and confirm standards mode.