PHP 7.0.6 Released

    The DOMXPath class

    (PHP 5, PHP 7)

    Introduction

    Supports XPath 1.0

    Class synopsis

    DOMXPath {
    /* Properties */
    public DOMDocument $document ;
    /* Methods */
    public __construct ( DOMDocument $doc )
    public mixed evaluate ( string $expression [, DOMNode $contextnode [, bool $registerNodeNS = true ]] )
    public DOMNodeList query ( string $expression [, DOMNode $contextnode [, bool $registerNodeNS = true ]] )
    public bool registerNamespace ( string $prefix , string $namespaceURI )
    public void registerPhpFunctions ([ mixed $restrict ] )
    }

    Properties

    document

    Table of Contents

    User Contributed Notes

    Mark Omohundro, ajamyajax dot com
    7 years ago
    <?php
    // to retrieve selected html data, try these DomXPath examples:

    $file = $DOCUMENT_ROOT. "test.html";
    $doc = new DOMDocument();
    $doc->loadHTMLFile($file);

    $xpath = new DOMXpath($doc);

    // example 1: for everything with an id
    //$elements = $xpath->query("//*[@id]");

    // example 2: for node data in a selected id
    //$elements = $xpath->query("/html/body/div[@id='yourTagIdHere']");

    // example 3: same as above with wildcard
    $elements = $xpath->query("*/div[@id='yourTagIdHere']");

    if (!    is_null($elements)) {
      foreach (    $elements as $element) {
        echo     "<br/>[". $element->nodeName. "]";

            $nodes = $element->childNodes;
        foreach (    $nodes as $node) {
          echo     $node->nodeValue. "\n";
        }
      }
    }
    ?>
    archimedix32783262 at mailinator dot com
    1 year ago
    Note that evaluate() will use the same encoding as the XML document.

    So if you have a UTF-16 XML, you will have to query using UTF-16 strings.

    You can use iconv() to convert from your code's encoding to the target encoding for better legibility.
    dhz
    5 years ago
    I just spent far too much time chasing this one....

    When running an xpath query on a table be careful about table internal nodes (ie: <tr></tr>, and <td></td>).  If the master <table> tag is missing, then query() (and likely evaluate() also) will return unexpected results.

    I had a DOMNode with a structure like this:

    <td>
        <table></table>
        <table>
            <tr>
                <td></td>
            </tr>
            <tr>
                <td></td>
                <td></td>
            </tr>
        </table>
    </td>

    Upon which I was trying to do a relative query (ie: <?php $xpath_obj->query('my/x/path', $relative_node); ?>).

    But because of the lone outer <td></td> tags, the inner tags were being invalidated, while the nodes were still recognized.  Meaning that the following query would work:

    <?php $xpath_obj->query('*[2]/*[*[2]]', $relative_node); ?>

    But when replacing any of the "*" tokens with the corresponding (and valid) "table", "tr", or "td" tokens the query would inexplicably break.
    david at lionhead dot nl
    6 years ago
    When using DOMXPath and having a default namespace. Consider using an intermediate function to add the default namespace to all queries:

    <?php
    // The default namespace: x:xmlns="http://..."
    $path="/Book/Title";
    $path=preg_replace("\/([a-zA-Z])","/x:$1",$path);

    // Result: /x:Book/x:Title
    ?>
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