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.
Parameters
elementId
The unique id value for an element.
Return Values
Returns the DOMElement or NULL if the element is
not found.
Examples
Example 1. DOMDocument->getElementById() Example
<?php
$doc = new DomDocument;
// We need to validate our document before refering to the id $doc->validateOnParse = true; $doc->Load('book.xml');
echo "The element whose id is books is: " . $doc->getElementById('books')->tagName . "\n";