PHP: DOMDocument->getElementById()

DOMDocument->getElementById()

richard at 2006 dot atterer dot net
05-Jun-2006 12:51


OK, so maybe PHP's getElementById() is behaving according to spec, but it does not have the behaviour that people *want*...

Below is a global getElementById() function (i.e. not a DOMDocument method) which recursively searches through a document for a certain id value.



/* Find the first element in the document (sub)tree whose id attribute

   has the value $id. By default, the entire document is searched - pass

   a non-NULL value in $node to search only the subtree below $node. */

function getElementById(DOMDocument $doc, /*string*/ $id,

                        DOMNode $node = NULL) {

  if ($node === NULL) return getElementById($doc, $id, $doc->documentElement);

  $children = $node->childNodes;

  for ($i = 0; $i < $children->length; ++$i) {

    $elem = $children->item($i);

    if (!($elem instanceof DOMElement)) continue;

    if ($elem->getAttribute('id') == $id) return $elem;

    $ret = getElementById($doc, $id, $elem);

    if ($ret !== NULL) return $ret;

  }

  return NULL;

}

Tangui dot Le-Pense at laposte dot net
08-Apr-2006 06:00


Validating a document from a DTD so as to use getElementById is sometimes impossible (for example when the head and body elements are not included yet in a XHtml document : the validation failed).

Fortunately, xml:id is supported by this function :)

That may be useful.

http://www.w3.org/TR/xml-id/

20-Dec-2005 07:04


If you're trying to use getElementById with a xml file validated on a xsd file you must first use the schemaValidate function or getElementById will return null

Example:



  $dom = new DomDocument();

  $dom->load("users.xml");

  $dom->schemaValidate("users.xsd");



  $curruser = $dom->getElementById($user->name);

bart at mediawave dot nl
11-Sep-2005 04:46


It seems getElementById works fine without setting validateOnParse to true. Which is nice since setting this to true caused some performance problems with my script.

rafaeltovar at nodo50 dot org
04-Aug-2005 01:31


Import a part to xml file to node of DOMDocument:



You have do put the correct DTD for ID attribute on XML file:



//----menu.xml----



<?xml version="1.0" encoding="iso-8859-1"?>

<!DOCTYPE menu [

   <!ELEMENT menu (item+)>

   <!ATTLIST menu id ID #REQUIRED>

   <!ELEMENT item (name, url)>

   <!ELEMENT name (#PCDATA)>

   <!ELEMENT url (#PCDATA)>

]>



<menu id="menu">

    <item>

        <name>item 1</name>

        <url>item1.php</url>

    </item>

    <item>

        <name>item 2</name>

        <url>item2.php</url>

    </item>

    <item>

        <name>item 3</name>

        <url>item3.php</url>

    </item>

    <item>

        <name>item 4</name>

        <url>item4.php</url>

    </item>

</menu>

//--------------------



<?

 $dom  = new DOMDocument('1.0', 'UTF-8');

 $page = $dom->createElement('page');

 $page = $dom->appendChild($page);

 

 // Load a file

 $domMenu  = new DOMDocument();

 $domMenu->validateOnParse = true;

 $domMenu->load("xml/menu.xml");

 

 // Use getElementById()

 $element=$domMenu->getElementById("menu");

 

 $menu = $dom->importNode($element, true);

 

 $page->appendChild($menu);



?>

chregu at php dot net
02-Jul-2004 04:37


http://wiki.bitflux.org/GetElementById_Pitfalls has an overview, of how to make getElementById work with aribtrary XML documents.

DOMDocument->getElementById()

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