The DOM extension in PHP comes with extensive functionality with which we can perform various operations on XML and HTML documents. We can dynamically construct a DOM object, load a DOM document from a HTML file or a string with HTML tag tree. We can also save the DOM document to a XML file, or extract the DOM tree from a XML document.
The DOMDocument class is one the most important classes defined in the DOM extension.
$obj=newDOMDocument($version="1.0",$encoding="")
It represents an entire HTML or XML document; serves as the root of the document tree. The DOMDocument class includes definitions of a number of static methods, some of which are introduced here −
| Sr.No | Methods & Description |
|---|---|
| 1 | createElementCreate new element node |
| 2 | createAttributeCreate new attribute |
| 3 | createTextNodeCreate new text node |
| 4 | getElementByIdSearches for an element with a certain id |
| 5 | getElementsByTagNameSearches for all elements with given local tag name |
| 6 | loadLoad XML from a file |
| 7 | loadHTMLLoad HTML from a string |
| 8 | loadHTMLFileLoad HTML from a file |
| 9 | loadXMLLoad XML from a string |
| 10 | saveDumps the internal XML tree back into a file |
| 11 | saveHTMLDumps the internal document into a string using HTML formatting |
| 12 | saveHTMLFileDumps the internal document into a file using HTML formatting |
| 13 | saveXMLDumps the internal XML tree back into a string |
Example
Let us use the following HTML file for this example −
<html><head><title>Tutorialspoint</title></head><body><h2>Course details</h2><table border = "0"><tbody><tr><td>Android</td><td>Gopal</td><td>Sairam</td></tr><tr><td>Hadoop</td><td>Gopal</td><td>Satish</td></tr><tr><td>HTML</td><td>Gopal</td><td>Raju</td></tr><tr><td>Web technologies</td><td>Gopal</td><td>Javed</td></tr><tr><td>Graphic</td><td>Gopal</td><td>Satish</td></tr><tr><td>Writer</td><td>Kiran</td><td>Amith</td></tr><tr><td>Writer</td><td>Kiran</td><td>Vineeth</td></tr></tbody></table></body></html>
We shall now extract the Document Object Model from the above HTML file by calling the loadHTMLFile() method in the following PHP code −
<?php
/*** a new dom object ***/
$dom = new domDocument;
/*** load the html into the object ***/
$dom->loadHTMLFile("hello.html");
/*** discard white space ***/
$dom->preserveWhiteSpace = false;
/*** the table by its tag name ***/
$tables = $dom->getElementsByTagName('table');
/*** get all rows from the table ***/
$rows = $tables[0]->getElementsByTagName('tr');
/*** loop over the table rows ***/
foreach ($rows as $row) {
/*** get each column by tag name ***/
$cols = $row->getElementsByTagName('td');
/*** echo the values ***/
echo 'Designation: '.$cols->item(0)->nodeValue.'<br />';
echo 'Manager: '.$cols->item(1)->nodeValue.'<br />';
echo 'Team: '.$cols->item(2)->nodeValue;
echo '<hr />';
}
?>
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