Sto cercando di validare il mio sito con W3c ma di da il seguente errore:
The validator has found the following problem(s) prior to validation, which should be addressed in priority:
DOCTYPE Override in effect!
The detected DOCTYPE Declaration "<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">" has been suppressed and the DOCTYPE for "HTML 4.01 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.
Validation Output: 1 Error
Line 17, Column 6: end tag for "HEAD" which is not finished.
Most likely, You nested tags and closed them in the wrong order. For example <p><em>...</p> is not acceptable, as <em> must be closed before <p>. Acceptable nesting is: <p><em>...</em></p>
Another possibility is that you used an element which requires a child element that you did not include. Hence the parent element is "not finished", not complete. For instance, in HTML the <head> element must contain a <title> child element, lists (ul, ol, dl) require list items (li, or dt, dd), and so on.