DOMDocument
PHP Manual

DOMDocument::getElementById

(PHP 5)

DOMDocument::getElementByIdSearches for an element with a certain id

Descrizione

public DOMElement DOMDocument::getElementById ( string $elementId )

This function is similar to DOMDocument::getElementsByTagName but searches for an element with a given id.

For this function to work, you will need either to set some ID attributes with DOMElement::setIdAttribute or a DTD which defines an attribute to be of type ID. In the later case, you will need to validate your document with DOMDocument::validate or DOMDocument::$validateOnParse before using this function.

Elenco dei parametri

elementId

The unique id value for an element.

Valori restituiti

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

Esempi

Example #1 DOMDocument::getElementById() Example

I seguenti esempi utilizzano book.xml il cui contenuto è:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE books [
  <!ELEMENT books   (book+)>
  <!ELEMENT book    (title, author+, xhtml:blurb?)>
  <!ELEMENT title   (#PCDATA)>
  <!ELEMENT blurb   (#PCDATA)>
  <!ELEMENT author  (#PCDATA)>
  <!ATTLIST books   xmlns        CDATA  #IMPLIED>
  <!ATTLIST books   xmlns:xhtml  CDATA  #IMPLIED>
  <!ATTLIST book    id           ID     #IMPLIED>
  <!ATTLIST author  email        CDATA  #IMPLIED>
]>
<?xml-stylesheet type="text/xsl" href="style.xsl"?>
<books xmlns="http://books.php/" xmlns:xhtml="http://www.w3.org/1999/xhtml">
  <book id="php-basics">
    <title>PHP Basics</title>
    <author email="[email protected]">Jim Smith</author>
    <author email="[email protected]">Jane Smith</author>
    <xhtml:blurb><![CDATA[
<p><em>PHP Basics</em> provides an introduction to PHP.</p>
]]></xhtml:blurb>
  </book>
  <book id="php-advanced">
    <title>PHP Advanced Programming</title>
    <author email="[email protected]">Jon Doe</author>
  </book>
</books>
<?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 'php-basics' is: " $doc->getElementById('php-basics')->tagName "\n";

?>

Il precedente esempio visualizzerà:

The element whose id is 'php-basics' is: book 

Vedere anche:


DOMDocument
PHP Manual