You can use this in this way.
$doc = new DOMDocument('1.0', 'UTF-8');
$doc->loadHTML($content); // html content
$xpath = new DOMXPath($doc);
$doc->normalizeDocument();
Note that, you can use $doc->normalizeDocument(); at any point of time.(PHP 5, PHP 7, PHP 8)
DOMDocument::normalizeDocument β ΠΠΎΡΠΌΠ°Π»ΠΈΠ·ΡΠ΅Ρ Π΄ΠΎΠΊΡΠΌΠ΅Π½Ρ
ΠΡΠΎΡ ΠΌΠ΅ΡΠΎΠ΄ ΡΠ°Π±ΠΎΡΠ°Π΅Ρ ΡΠ°ΠΊ, ΠΊΠ°ΠΊ Π΅ΡΠ»ΠΈ Π±Ρ Π΄ΠΎΠΊΡΠΌΠ΅Π½Ρ ΡΠΎΡ ΡΠ°Π½ΠΈΠ»ΠΈ, Π° Π·Π°ΡΠ΅ΠΌ Π·Π°Π³ΡΡΠ·ΠΈΠ»ΠΈ, β ΠΏΡΠΈΠ²ΠΎΠ΄ΠΈΡ Π΄ΠΎΠΊΡΠΌΠ΅Π½Ρ ΠΊ Β«Π½ΠΎΡΠΌΠ°Π»ΡΠ½ΠΎΠΉΒ» ΡΠΎΡΠΌΠ΅.
Π‘ΠΈΠ³Π½Π°ΡΡΡΠ° ΡΡΠ½ΠΊΡΠΈΠΈ Π½Π΅ ΡΠΎΠ΄Π΅ΡΠΆΠΈΡ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ².
Π€ΡΠ½ΠΊΡΠΈΡ Π½Π΅ Π²ΠΎΠ·Π²ΡΠ°ΡΠ°Π΅Ρ Π·Π½Π°ΡΠ΅Π½ΠΈΡ ΠΏΠΎΡΠ»Π΅ Π²ΡΠΏΠΎΠ»Π½Π΅Π½ΠΈΡ.
You can use this in this way.
$doc = new DOMDocument('1.0', 'UTF-8');
$doc->loadHTML($content); // html content
$xpath = new DOMXPath($doc);
$doc->normalizeDocument();
Note that, you can use $doc->normalizeDocument(); at any point of time.