DOMDocument->getElementById()

Searches for an element with a certain id ()

DOMDocument {
  DOMElement getElementById(string elementId);
}

This function is similar to DOMDocument->getElementsByTagName() but searches for an element with a given 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.

参数

elementId

The unique id value for an element.

返回值

Returns the DOMElement or NULL if the element is not found.

范例

例 466. 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";

?>

上例将输出:

The element whose id is books is: chapter