I have problems at xhtml strict 1.0 validation

Question

How should I fix these problems at the validation?

Error Line 15, Column 10: there is no attribute "id" nav id="kipozicional"

Error Line 15, Column 24: element "nav" undefined nav id="kipozicional"

Error Line 18, Column 8: element "header" undefined

Error Line 36, Column 6: element "main" undefined

Error Line 37, Column 9: element "article" undefined

Answer 1

The elements you are using were all introduced in HTML 5. XHTML 1.0 is too old to support them.

Your options:

• Switch to HTML 5 (you could use the XML serialisation if you wanted)
• Replace the elements with ones in XHTML 1 (e.g. divs)
• Have invalid XHTML

I recommend switching to HTML 5.