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(PHP 5, PHP 7, PHP 8)

DOMAttr::isId Checks if attribute is a defined ID


public DOMAttr::isId(): bool

This function checks if the attribute is a defined ID.

According to the DOM standard this requires a DTD which defines the attribute ID to be of type ID. You need to validate your document with DOMDocument::validate or DOMDocument::$validateOnParse before using this function.


This function has no parameters.

Return Values

Returns true on success or false on failure.


Example #1 DOMAttr::isId() Example


= new DomDocument;

// We need to validate our document before referring to the id
$doc->validateOnParse = true;

// We retrieve the attribute named id of the chapter element
$attr = $doc->getElementsByTagName('chapter')->item(0)->getAttributeNode('id');

var_dump($attr->isId()); // bool(true)


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