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    DOMDocument::createAttributeNS

    (PHP 5, PHP 7, PHP 8)

    DOMDocument::createAttributeNS — Create new attribute node with an associated namespace

    Description

    public DOMDocument::createAttributeNS(?string $namespace, string $qualifiedName): DOMAttr|false

    This function creates a new instance of class DOMAttr. This node will not show up in the document unless it is inserted with (e.g.) DOMNode::appendChild().

    Parameters

    namespace

    The URI of the namespace.

    qualifiedName

    The tag name and prefix of the attribute, as prefix:tagname.

    Return Values

    The new DOMAttr or false if an error occurred.

    Errors/Exceptions

    DOM_INVALID_CHARACTER_ERR

    Raised if qualifiedName contains an invalid character.

    DOM_NAMESPACE_ERR

    Raised if qualifiedName is a malformed qualified name, or if qualifiedName has a prefix and namespace is null.

    Changelog

    Version Description
    8.3.0 Calling this method without specifying a prefix will now choose a prefix instead of assuming the default namespace. Previously this would create an attribute without a prefix and incorrectly apply the namespace to the owner element because default namespaces don't apply on attributes.
    8.3.0 Calling this method using a prefix that was already declared on the owner element with a different namespace URI will now change the new prefix to avoid creating namespace conflicts. This aligns the behaviour with the DOM specification. Previously this threw a DOMException with code DOM_NAMESPACE_ERR.

    See Also

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    User Contributed Notes 1 note

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    10
    _ michael
    14 years ago
    If a new namespace is introduced while creating and inserting an attribute, createAttributeNS() does not behave in the same way as createElementNS().

    (1) Location: With createAttributeNS(), the new namespace is declared at the level of the document element. By contrast, createElementNS() declares the new namespace at the level of the affected element itself.

    (2) Timing: With createAttributeNS(), the new namespace is declared in the document as soon as the attribute is created - the attribute does not actually have to be inserted. createElementNS() doesn't affect the document as long as the element is not inserted.

    An example:

    <?php
       
        $source     = <<<XML
    <?xml version="1.0" encoding="UTF-8"?>
    <root><tag></tag></root>
    XML;
       
            /*
        
         I. createAttributeNS:
         * a new namespace shows up immediately, even without insertion of the attribute
         * the new namespace is declared at the level of the document element
        
        */
       
            $doc = new DOMDocument( '1.0' );
            $doc->loadXML( $source );
       
            // (1) We just create a "namespace'd" attribute without appending it to any element.
            $attr_ns = $doc->createAttributeNS( '{namespace_uri_here}', 'example:attr' );
       
        print     $doc->saveXML() . "\n";
       
            /*
          Result: The namespace declaration appears, having been added to the document element. Output:
         
          <?xml version="1.0" encoding="UTF-8"?>
          <root xmlns:example="{namespace_uri_here}"><tag/></root>
         
        */
       
        // (2) Next, we give the attribute a value and insert it.
            $attr_ns->value = 'value';
            $doc->getElementsByTagName( 'tag' )->item(0)->appendChild( $attr_ns );
       
        print     $doc->saveXML() . "\n";
       
            /*
          Result: The "namespace'd" attribute shows up as well. Output:
         
          <?xml version="1.0" encoding="UTF-8"?>
          <root xmlns:example="{namespace_uri_here}"><tag example:attr="value"/></root>
         
        */
       
        /*
        
         II. createElementNS:
         * a new namespace shows up only when the element is inserted
         * the new namespace is declared at the level of the inserted element
        
        */
       
            $doc = new DOMDocument( '1.0' );
            $doc->loadXML( $source );
       
            // (1) We create a "namespace'd" element without inserting it into the document.
            $elem_ns = $doc->createElementNS( '{namespace_uri_here}', 'example:newtag' );
       
        print     $doc->saveXML() . "\n";
       
            /*
          Result: The document remains unchanged. Output:
         
          <?xml version="1.0" encoding="UTF-8"?>
          <root><tag/></root>
         
        */
       
        // (2) Next, we insert the new element.
            $doc->getElementsByTagName( 'tag' )->item(0)->appendChild( $elem_ns );
       
        print     $doc->saveXML() . "\n";
       
            /*
          Result: The namespace declaration appears, and it is embedded in the element using it. Output:
         
          <?xml version="1.0" encoding="UTF-8"?>
          <root><tag><example:newtag xmlns:example="{namespace_uri_here}"/></tag></root>
         
        */
       
    ?>
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