DOMDocument::getElementsByTagName
(PHP 5)
DOMDocument::getElementsByTagName — Searches for all elements with given local tag name
Description
This function returns a new instance of class DOMNodeList containing all the elements with a given local tag name.
Parameters
-
name -
The local name (without namespace) of the tag to match on. The special value * matches all tags.
Return Values
A new DOMNodeList object containing all the matched elements.
Examples
Example #1 Basic Usage Example
<?php
$xml = <<< XML
<?xml version="1.0" encoding="utf-8"?>
<books>
<book>Patterns of Enterprise Application Architecture</book>
<book>Design Patterns: Elements of Reusable Software Design</book>
<book>Clean Code</book>
</books>
XML;
$dom = new DOMDocument;
$dom->loadXML($xml);
$books = $dom->getElementsByTagName('book');
foreach ($books as $book) {
echo $book->nodeValue, PHP_EOL;
}
?>
The above example will output:
Patterns of Enterprise Application Architecture Design Patterns: Elements of Reusable Software Design Clean Code
See Also
- DOMDocument::getElementsByTagNameNS() - Searches for all elements with given tag name in specified namespace
- PHP Руководство
- Функции по категориям
- Индекс функций
- Справочник функций
- Обработка XML
- Document Object Model
- Функция DOMDocument::__construct() - Создание нового DOMDocument объекта
- Функция DOMDocument::createAttribute() - Создает новый атрибут
- Функция DOMDocument::createAttributeNS() - Создает новый узел-атрибут с соответствующим ему пространством имен
- Функция DOMDocument::createCDATASection() - Создает новый cdata узел
- Функция DOMDocument::createComment() - Создает новый узел-комментарий
- Функция DOMDocument::createDocumentFragment() - Создание фрагмента докуента
- Функция DOMDocument::createElement() - Создает новый узел-элемент
- Функция DOMDocument::createElementNS() - Создание нового узла-элемента с соответствующим пространством имен
- Функция DOMDocument::createEntityReference() - Создание нового узла-ссылки на сущность
- Функция DOMDocument::createProcessingInstruction() - Создает новый PI-узел
- Функция DOMDocument::createTextNode() - Создает новый текстовый узел
- Функция DOMDocument::getElementById() - Ищет элемент с заданным id
- Функция DOMDocument::getElementsByTagName() - Ищет все элементы с заданным локальным именем
- Функция DOMDocument::getElementsByTagNameNS() - Ищет элементы с заданным именем в определенном пространстве имен
- Функция DOMDocument::importNode() - Импорт узла в текущий документ
- Функция DOMDocument::load() - Загрузка XML из файла
- Функция DOMDocument::loadHTML() - Загрузка HTML из строки
- Функция DOMDocument::loadHTMLFile() - Загрузка HTML из файла
- Функция DOMDocument::loadXML() - Загрузка XML из строки
- Функция DOMDocument::normalizeDocument() - Нормализует документ
- Функция DOMDocument::registerNodeClass() - Регистрация расширенного класса, используемого для создания базового типа узлов
- Функция DOMDocument::relaxNGValidate() - Производит проверку документа на правильность построения посредством relaxNG
- Функция DOMDocument::relaxNGValidateSource() - Проверяет документ посредством relaxNG
- Функция DOMDocument::save() - Сохраняет XML дерево из внутреннего представления в файл
- DOMDocument::saveHTML
- DOMDocument::saveHTMLFile
- Функция DOMDocument::saveXML() - Сохраняет XML дерево из внутреннего представления в виде строки
- Функция DOMDocument::schemaValidate() - Проверяет действительности документа, основываясь на заданной схеме
- Функция DOMDocument::schemaValidateSource() - Проверяет действительность документа, основываясь на схеме
- Функция DOMDocument::validate() - Проверяет документ на соответствие его DTD
- Функция DOMDocument::xinclude() - Проводит вставку XInclude разделов в объектах DOMDocument
Коментарии
Here is an example of getElementsByTagName():
<?php
$xml =<<<EOT
<?xml version="1.0"?>
<config>
<section id="section1">
<param name="param1">value1</param>
<param name="param2">value2</param>
</section>
<section id="section2">
<param name="param3">value3</param>
</section>
</config>
EOT;
$dom = new DomDocument;
$dom->preserveWhiteSpace = FALSE;
$dom->loadXML($xml);
$params = $dom->getElementsByTagName('param');
foreach ($params as $param) {
echo $param -> getAttribute('name').'<br>';
}
?>
Expected result:
--------------
param1
param2
param3
I don't know if this is that obvious but it was not for me, so in addition to gem at rellim dot com's posting:
adding
<?php
echo $param -> nodeValue.'<br>';
?>
to the loop will output
value1
value2
value3
in response to tildy at pr dot hu
my preferred way is (in example to gather country data from an iso 3166 xml flie)
$countries = new DOMDocument();
$countries->load("./lib/iso_3166.xml");
$countriesList = $countries->getElementsByTagName("ISO_3166-1_Entry");
foreach($countriesList as $country) {
$values = $country->getElementsByTagName("*");
foreach($values as $node) {
echo $node->nodeName."=".$node->nodeValue;
}
}
Return if there are no matches is an empty DOMNodeList. Check using length property, e.g.:
<?php
$nodes=$domDocument->getElementsByTagName('book') ;
if ($nodes->length==0) {
// no results
}
?>
Following Example is of multiple attributes and multiple child nodes. this is being used to make joomla plugin for bulk upload of articles. Gurmukh Singh Bhatti
<?php
$xml =<<<EOT
<?xml version="1.0"?>
<root>
<section name="Section1">
<category id="Category1" name="google">
<arti name="article1">
<p>any html code here</p>
<b>my name is so so</b>
</arti>
<arti name="article2">value2</arti>
<arti name="article3">value3</arti>
<arti name="article4">value4</arti>
</category>
<category id="Category2" name="yahoo">
<arti name="articleSection2">Test value</arti>
</category>
</section>
<section name="Section2">
<category id="category1_of_section2" name="msn">
<arti name="article2">value1</arti>
<arti name="article3">value2</arti>
</category>
<category id="Category2_of_section2" name="webcare">
<arti name="param3">value4</arti>
</category>
</section>
</root>
EOT;
$dom = new DomDocument;
$dom->preserveWhiteSpace = FALSE;
$dom->loadXML($xml);
$params = $dom->getElementsByTagName('section'); // Find Sections
$k=0;
foreach ($params as $param) //go to each section 1 by 1
{
echo "Section Attribute :-> ".$params->item($k)->getAttribute('name')."<br>"; //get section attribute
$params2 = $params->item($k)->getElementsByTagName('category'); //digg categories with in Section
$i=0; // values is used to iterate categories
foreach ($params2 as $p) {
echo " - Category Attribute Name :-> ".$params2->item($i)->getAttribute('name')."<br>"; //get Category attributes
$params3 = $params2->item($i)->getElementsByTagName('arti'); //dig Arti into Categories
$j=0;//values used to interate Arti
foreach ($params3 as $p2)
{
echo " - Article Attribute Name : ".$params3->item($j)->getAttribute('name').""; //get arti atributes
echo " Value : ".$params3->item($j)->nodeValue."<br>"; //get Node value ;
$j++;
}
$i++;
}
$k++;
}
?>
output :
Section Attribute :-> Section1
- Category Attribute Name :-> google
- Article Attribute Name : article1 Value : any html code heremy name is so so
- Article Attribute Name : article2 Value : value2
- Article Attribute Name : article3 Value : value3
- Article Attribute Name : article4 Value : value4
- Category Attribute Name :-> yahoo
- Article Attribute Name : articleSection2 Value : Test value
Section Attribute :-> Section2
- Category Attribute Name :-> msn
- Article Attribute Name : article2 Value : value1
- Article Attribute Name : article3 Value : value2
- Category Attribute Name :-> webcare
- Article Attribute Name : param3 Value : value4
Problem:
You have an XML document that contains filename references to, say, images. Each filename reference is defined by <file>filename.ext</file> tag. You'd like to perform perform additional validation, say, after running the XML document through XSD validation. The additional validation can be any of your choice, in this example, it would be ideal to convert the PHP code to a function. The function would then determine if the images exist and return either an integer value or a boolean.
<?xml version="1.0"?>
<root>
<box>
<file>example.png</file>
</box>
<content>
<item>
<image><file>example2.png</file></image>
<caption>The above image is an example</caption>
</item>
</content>
</root>
Solution:
<?php
$dom = new DomDocument();
$dom->prevservWhiteSpace = false;
if (!@$dom->load("example.xml")) {
echo "example.xml doesn't exist!\n";
return;
}
$imageList = $dom->getElementsByTagName('file');
$imageCnt = $imageList->length;
for ($idx = 0; $idx < $imageCnt; $idx++) {
print $imageList->item($idx)->nodeValue . "\n";
}
?>
The above PHP code could easily be turned into a function that returns an array of image filenames, an integer value relative to the number of images found, etc.
Hope this is helpful.
The following takes a list of news items from an XML file (or an RSS feed), assigning it to an array first for a name value pair and then generating an HTML list.
<?php
$xml =<<<EOT
<?xml version="1.0" encoding="ISO-8859-1"?>
<news>
<item>
<title>News 1</title>
<created>04/2/2010 08:00 EST</created>
<url>http://news.example.com/news.pdf</url>
</item>
<item>
<title>News 2</title>
<created>04/25/2010 08:00 EST</created>
<url>http://news.example.com/news.pdf</url>
</item>
<item>
<title>News 3</title>
<created>04/27/2010 08:00 EST</created>
<url>http://news.example.com/news.pdf</url>
</item>
</news>
EOT;
$doc = new DOMDocument();
if ($doc->loadXML($xml)) {
$items = $doc->getElementsByTagName('item');
$headlines = array();
foreach($items as $item) {
$headline = array();
if($item->childNodes->length) {
foreach($item->childNodes as $i) {
$headline[$i->nodeName] = $i->nodeValue;
}
}
$headlines[] = $headline;
}
if(!empty($headlines)) {
$hc = 0;
echo '<ul>';
foreach($headlines as $headline) {
if(++$hc <= 3) {
echo '<li>'
.'<a href="'.$headline['url'].'" target="_blank">'
.'<span>'.date('F j, Y', strtotime($headline['created'])).'</span><br />'
.$headline['title']
.'</a>'
.'</li>';
}
}
echo '</ul>';
}
}
?>
Note that when using getElementsByTagName that it is a dynamic list. Thus if you have code which adjusts the DOM structure it will change the results of the getElementsByTagName results list.
The following code iterates through a complete set of results and changes them all to a new tag:
<?php
$nodes = $xml->getElementsByTagName ("oldtag");
$nodeListLength = $nodes->length; // this value will also change
for ($i = 0; $i < $nodeListLength; $i ++)
{
$node = $nodes->item(0);
// some code to change the tag name from "oldtag" to something else
// e.g. encrypting a tag element
}
?>
Since the list is dynamically updating, $nodes->item(0) is the next "unchanged" tag.
My first post!
And this is how I get elements by attribute and its value.
For an example, if I want to grab all DIV tags with class name 'className', then...
<?php
$some_link = 'some website';
$tagName = 'div';
$attrName = 'class';
$attrValue = 'className';
$dom = new DOMDocument;
$dom->preserveWhiteSpace = false;
@$dom->loadHTMLFile($some_link);
$html = getTags( $dom, $tagName, $attrName, $attrValue );
echo $html;
function getTags( $dom, $tagName, $attrName, $attrValue ){
$html = '';
$domxpath = new DOMXPath($dom);
$newDom = new DOMDocument;
$newDom->formatOutput = true;
$filtered = $domxpath->query("//$tagName" . '[@' . $attrName . "='$attrValue']");
// $filtered = $domxpath->query('//div[@class="className"]');
// '//' when you don't know 'absolute' path
// since above returns DomNodeList Object
// I use following routine to convert it to string(html); copied it from someone's post in this site. Thank you.
$i = 0;
while( $myItem = $filtered->item($i++) ){
$node = $newDom->importNode( $myItem, true ); // import node
$newDom->appendChild($node); // append node
}
$html = $newDom->saveHTML();
return $html;
}
?>
Please, improve it, and share it.
My first try to get a stable solution with this function, failed with this Exception:
"Fatal error: Call to undefined method DOMNodeList::getElementsByTagName()"
This is the xml snipplet:
<?xml version="1.0" encoding="UTF-8"?>
<root>
<component>
<properties>
....<any element>
</properties>
</component>
</root>
So the php code to climb along the elements is:
<?php
$src = new DOMDocument('1.0', 'utf-8');
$src->formatOutput = true;
$src->preserveWhiteSpace = false;
//Loading extern file
$src->load('../xml/Item_component.xml');
//Check each child of first indexed branch node of: <component>
//First get element after root element: <component>
//1st level
$component = $src->getElementsByTagName('component')->item(0);
//2nd level, get next element after component, here it fails!!
$properties = $component->getElementsByTagName('properties')->item(0);
...
?>
I realised, that there is a different when using different libxml2 versions on Apache2. This code will fail with libxml2 version 2.6.23 and PHP version 5.2.6
--
->It works fine with libxml2 version 2.6.32 and PHP version 5.2.6-3ubuntu4.6
->...and finally it also works with libxml2 2.7.7 and PHP >= 5.3
So if you bored to search for solutions with DOM like I did, please ensure that your www environment has the correct libxml2 / PHP Version installed on your apache2 server.
This is a very simplistic way to traverse xml nodes and childnodes using the DOMDocument class
<?php
$xml ='<?xml version="1.0" encoding="utf-8"?>
<root>
<Parent>
<child>child 1</child>
<child>child 2</child>
<child>child 3</child>
<subParent>
<Grandchild>Grandchild 1</Grandchild>
<Grandchild>Grandchild 2</Grandchild>
<Grandchild>Grandchild 3</Grandchild>
</subParent>
</Parent>
<Parent>
<child>child 4</child>
<child>child 5</child>
<child>child 6</child>
<subParent>
<Grandchild>Grandchild 4</Grandchild>
<Grandchild>Grandchild 5</Grandchild>
<Grandchild>Grandchild 6</Grandchild>
</subParent>
</Parent>
</root>';
$doc = new DOMDocument();
$doc->preserveWhiteSpace = false;
$doc->loadXML($xml);
$i=0;
while(is_object($finance = $doc->getElementsByTagName("Parent")->item($i)))
{
foreach($finance->childNodes as $nodename)
{
if($nodename->nodeName=='subParent')
{
foreach($nodename->childNodes as $subNodes)
{
echo $subNodes->nodeName." - ".$subNodes->nodeValue."<br>";
}
}
else
{
echo $nodename->nodeName." - ".$nodename->nodeValue."<br>";
}
}
$i++;
}
?>
Here is a function to convert the populated tables in and HTML document into an array.
<?php
//Create an array containing all the populated tables in an HTML page
//Returned array: tables_to_array[table number][row number][column number]
function tables_to_array ($url) {
$htmlDocDom = new DOMDocument();
@$htmlDocDom->loadHTMLFile($url);
$htmlDocDom->preserveWhiteSpace = false;
$tableCounter = 0;
$htmlDocTableArray = array();
$htmlDocTables = $htmlDocDom->getElementsByTagName('table');
foreach ($htmlDocTables as $htmlDocTable) {
$htmlDocTableArray[$tableCounter] = array();
$htmlDocRows= $htmlDocTable->getElementsByTagName('tr');
$htmlDocRowCount = 0;
$htmlDocTableArray[$tableCounter] = array();
foreach ($htmlDocRows as $htmlDocRow) {
if (strlen($htmlDocRow->nodeValue) > 1)
{
$htmlDocColCount = 0;
$htmlDocTableArray[$tableCounter][$htmlDocRowCount] = array();
$htmlDocCols = $htmlDocRow->getElementsByTagName('td');
foreach ($htmlDocCols as $htmlDocCol) {
$htmlDocTableArray[$tableCounter][$htmlDocRowCount][] = $htmlDocCol->nodeValue;
$htmlDocColCount++;
}
$htmlDocRowCount++;
}
}
if ($htmlDocRowCount > 1) $tableCounter++;
}
return($htmlDocTableArray);
}
?>
I was in need of $dom->getElementsByTagName that would hist magic within a contextNode.
Why i needed getElementsByTagName instead of just simple using an xPath->query is because while looping through the returned nodelist, more nodes with the tagName i was looking for where created.
When using getElementsByTagName, the new nodes are "added" to the nodelist i already am looping through.
When using an xpath query, you wil only loop through the original nodelist, the newly created elements wil not appear in that nodelist.
I was already using an extended class on domDocument, so it was simple to create an kind of getElementsByTagName that would accept an contextNode.
<?php
class SmartDocument extends DOMDocument {
private $localDom;
public $xpath;
private $serialize = array('localDom');
private $elemName;
private $elemCounter;
/**
* Constructor
*/
function __construct() {
parent::__construct ( '1.0', 'UTF-8' );
$this->preserveWhiteSpace = false;
$this->recover = TRUE;
$this->xpath = new DOMXpath ( $this );
}
/**
* GetElementsByTagname within an contextNode
*
* @param string $name
* @param DomNode $contextNode
* @return DOMNode|NULL
*/
public function getElementsByTagNameContext($name, $contextNode) {
if($this->elemName!=$name) {
$this->elemCounter = 0;
$this->elemName =$name;
}
$this->elemLength = $this->xpath->evaluate('count(.//*[name()="'.$this->elemName.'"])', $contextNode);
while($this->elemCounter < $this->elemLength) {
$this->elemCounter++;
$nl = $this->xpath->query('.//*[name()="'.$this->elemName.'"]['.$this->elemCounter.']', $contextNode);
if($nl->length == 1) {
return $nl->item(0);
}
}
$this->elemLength = null;
$this->elemCounter = null;
$this->elemName = null;
return null;
}
}
?>
Usage:
<?php
$doc = new SmartDocument();
$doc->load('book.xml');
$nl = $doc->query('//books');
foreach($nl as $node) {
while($book = $doc->getElementsByTagNameContext('book', $node)) {
//When you now create new nodes within this loop as child or following-sibling of this node
// They show up within this loop
}
}
?>
If you want to move all nodes to another tag you can do it like that
Eg: replace <div> with nodes to <p> with the same nodes.
function replaceDomElementTag(DOMDocument $dom, DOMElement $node, string $tagName)
{
$newElement = $dom->createElement($tagName);
while ($node->childNodes->length)
$newElement->appendChild($node->childNodes[0]);
$node->parentNode->replaceChild($newElement, $node);
}
$dom = new DOMDocument();
replaceDomElementTag($dom, $divElementToReplace, 'p');