Postanowiłem sprawdzić kod xHTML w walidatorze. Wyskoczyły mi 2 błędy tej samej treści tylko w innych linijkach.
Treść błędów:
1.
Kod
Warning DOCTYPE Override in effect!
The detected DOCTYPE Declaration "<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">" has been suppressed and the DOCTYPE for "XHTML 1.0 Transitional" inserted instead, but even if no errors are shown below the document will not be Valid until you update it to reflect this new DOCTYPE.
The detected DOCTYPE Declaration "<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">" has been suppressed and the DOCTYPE for "XHTML 1.0 Transitional" inserted instead, but even if no errors are shown below the document will not be Valid until you update it to reflect this new DOCTYPE.
2.
Kod
Info Using Direct Input mode: UTF-8 character encoding assumed
Unlike the "by URI" and "by File Upload" modes, the "Direct Input" mode of the validator provides validated content in the form of characters pasted or typed in the validator's form field. This will automatically make the data UTF-8, and therefore the validator does not need to determine the character encoding of your document, and will ignore any charset information specified.
If you notice a discrepancy in detected character encoding between the the ?Direct Input? mode and other validator modes, this is likely to be the reason. It is neither a bug in the validator, nor in your document.
Unlike the "by URI" and "by File Upload" modes, the "Direct Input" mode of the validator provides validated content in the form of characters pasted or typed in the validator's form field. This will automatically make the data UTF-8, and therefore the validator does not need to determine the character encoding of your document, and will ignore any charset information specified.
If you notice a discrepancy in detected character encoding between the the ?Direct Input? mode and other validator modes, this is likely to be the reason. It is neither a bug in the validator, nor in your document.
Nie za bardzo wiem o co chodzi. Jeśli mógłby ktoś pomóc byłbym bardzo wdzięczny
EDIT:
Ustawiając ENCODING i DOCTYPE na automatyczne wyrzuca tylko błąd nr 2
Kod
Info Using Direct Input mode: UTF-8 character encoding assumed
Unlike the "by URI" and "by File Upload" modes, the "Direct Input" mode of the validator provides validated content in the form of characters pasted or typed in the validators form field. This will automatically make the data UTF-8, and therefore the validator does not need to determine the character encoding of your document, and will ignore any charset information specified.
If you notice a discrepancy in detected character encoding between the the ?Direct Input? mode and other validator modes, this is likely to be the reason. It is neither a bug in the validator, nor in your document.
Unlike the "by URI" and "by File Upload" modes, the "Direct Input" mode of the validator provides validated content in the form of characters pasted or typed in the validators form field. This will automatically make the data UTF-8, and therefore the validator does not need to determine the character encoding of your document, and will ignore any charset information specified.
If you notice a discrepancy in detected character encoding between the the ?Direct Input? mode and other validator modes, this is likely to be the reason. It is neither a bug in the validator, nor in your document.
Wielkość ma znaczenie. 
Na samym początku dokumentu xHTML musisz mieć następującą linijkę: 