(PHP 5)
DOMDocument::createAttributeNS — Create new attribute node with an associated namespace
This function creates a new instance of class DOMAttr. 此节点出现在文档中，除非是用诸如 DOMNode->appendChild() 等函数来将其插入。
namespaceURI
The URI of the namespace.
qualifiedName
The tag name and prefix of the attribute, as prefix:tagname.
The new DOMAttr or FALSE if an error occurred.
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
namespaceURI is NULL.
_ michael (2010-06-01 07:35:20)
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>
*/
?>