DOMDocument::createElement

(PHP 5, PHP 7, PHP 8)

DOMDocument::createElement — Create new element node

说明

public DOMDocument::createElement(string $localName, string $value = ""): DOMElement|false

This function creates a new instance of class DOMElement. 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。

参数

localName

The tag name of the element.

value

The value of the element. By default, an empty element will be created. The value can also be set later with DOMElement::$nodeValue.

The value is used verbatim except that the < and > entity references will escaped. Note that & has to be manually escaped; otherwise it is regarded as starting an entity reference. Also " won't be escaped.

返回值

Returns a new instance of class DOMElement or false if an error occurred.

错误／异常

DOM_INVALID_CHARACTER_ERR: Raised if localName contains an invalid character.

示例

示例 #1 Creating a new element and inserting it as root

<?php

$dom = new DOMDocument('1.0', 'utf-8');

$element = $dom->createElement('test', 'This is the root element!');

// We insert the new element as root (child of the document)
$dom->appendChild($element);

echo $dom->saveXML();
?>

以上示例会输出：

<?xml version="1.0" encoding="utf-8"?>
<test>This is the root element!</test>

示例 #2 Passing text containing an unescaped & as value

<?php
$dom = new DOMDocument('1.0', 'utf-8');
$element = $dom->createElement('foo', 'me & you');
$dom->appendChild($element);
echo $dom->saveXML();
?>

以上示例的输出类似于：

Warning: DOMDocument::createElement(): unterminated entity reference             you in /in/BjTCg on line 4
<?xml version="1.0" encoding="utf-8"?>
<foo/>

注释

注意:
The value will not be escaped. Use DOMDocument::createTextNode() to create a text node with escaping support.

参见

DOMNode::appendChild() - Adds new child at the end of the children
DOMDocument::createAttribute() - Create new attribute
DOMDocument::createAttributeNS() - Create new attribute node with an associated namespace
DOMDocument::createCDATASection() - Create new cdata node
DOMDocument::createComment() - Create new comment node
DOMDocument::createDocumentFragment() - Create new document fragment
DOMDocument::createElementNS() - Create new element node with an associated namespace
DOMDocument::createEntityReference() - Create new entity reference node
DOMDocument::createProcessingInstruction() - Creates new PI node
DOMDocument::createTextNode() - Create new text node

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＋添加备注

用户贡献的备注 9 notes

down

mikek dot nospam at nospam dot muonics dot com ¶

17 years ago

With regard to the note below about needing htmlentities to avoid warnings about unterminated entity references, I thought it worthwhile to mention that that you don't need to with createTextNode and DOMText::__construct.  If you mix both methods of setting text nodes and do (or don't) apply htmlentities consistently to all data to be displayed, you'll get &amp;s (or warnings and badly-formed xml).

It's probably in one's best interest to extend DOMElement and DOMDocument so that it creates a DOMText node and appends it, rather than passing it up to the DOMElement constructor.  Otherwise, good luck using (or not using) htmlentities in all the right places in your code, especially as code changes get made.

<?php

class XDOMElement extends DOMElement {
    function __construct($name, $value = null, $namespaceURI = null) {
        parent::__construct($name, null, $namespaceURI);
    }
}

class XDOMDocument extends DOMDocument {
    function __construct($version = null, $encoding = null) {
        parent::__construct($version, $encoding);
        $this->registerNodeClass('DOMElement', 'XDOMElement');
    }

    function createElement($name, $value = null, $namespaceURI = null) {
        $element = new XDOMElement($name, $value, $namespaceURI);
        $element = $this->importNode($element);
        if (!empty($value)) {
            $element->appendChild(new DOMText($value));
        }
        return $element;
    }
}

$doc1 = new XDOMDocument();
$doc1_e1 = $doc1->createElement('foo', 'bar & baz');
$doc1->appendChild($doc1_e1);
echo $doc1->saveXML();

$doc2 = new XDOMDocument();
$doc2_e1 = $doc2->createElement('foo');
$doc2->appendChild($doc2_e1);
$doc2_e1->appendChild($doc2->createTextNode('bar & baz'));
echo $doc2->saveXML();

?>

Text specified in createElement:
<?xml version=""?>
<foo>bar &amp; baz</foo>

Text added via createTextNode:
<?xml version=""?>
<foo>bar &amp; baz</foo>

down

yasindagli at gmail dot com ¶

15 years ago

To create elements with attributes,

<?php

function createElement($domObj, $tag_name, $value = NULL, $attributes = NULL)
{
    $element = ($value != NULL ) ? $domObj->createElement($tag_name, $value) : $domObj->createElement($tag_name);

    if( $attributes != NULL )
    {
        foreach ($attributes as $attr=>$val)
        {
            $element->setAttribute($attr, $val);
        }
    }

    return $element;
}

$dom = new DOMDocument('1.0', 'utf-8');

$elm = createElement($dom, 'foo', 'bar', array('attr_name'=>'attr_value'));

$dom->appendChild($elm);

echo $dom->saveXML();

?>

outputs : 
<?xml version="1.0" encoding="utf-8"?>
<foo attr_name="attr_value">bar</foo>

down

sergsokolenko at gmail dot com ¶

17 years ago

To avoid warning message "unterminated entity reference" you may use htmlentities() for escaping supplied value:
<?php
//...
$dom->createElement('name', htmlentities($text))
//...
?>

down

funkathustra ¶

12 years ago

Although the built-in DOM functions are great, since they're designed to support generic XML, generating HTML DOMs becomes particularly verbose. I ended up writing this function to drastically speed things up.
Instead of calling something like
<?php 
  $div = $dom->createElement("div");
  $div->setAttribute("class","MyClass");
  $div->setAttribute("id","MyID");
  $someOtherDiv->appendChild($div);
?>
you can accomplish the same thing with:
<?php
  $div = newElement("div", $someOtherDiv, "class=MyClass;id=MyID");
?>
The "key1=value;key2=value" syntax is really fast to use, but obviously doesn't hold up if your content has those characters in it. So, you can also pass it an array:
<?php
  $div = newElement("div", $someOtherDiv, array("class","MyClass"));
?>
Or an array of arrays, representing different attributes:
<?php
  $div = newElement("form", $someOtherDiv, array(array("method","get"), array("action","/refer/?id=5");
?>

Here's the function:

<?php
function newElement($type, $insertInto = NULL, $params=NULL, $content="")
    {
        $tempEl =  $this->dom->createElement($type, $content);
        if(gettype($params) == "string" && strlen($params) > 0)
        {
            $attributesCollection =split(";", $params);
            foreach($attributesCollection  as $attribute)
            {
                $keyvalue = split("=", $attribute);
                $tempEl->setAttribute($keyvalue[0], $keyvalue[1]);
            }
        }
        if(gettype($params) == "array")
        {
            if(gettype($params[0]) == "array")
            {
                foreach($params as $attribute)
                {
                    $tempEl->setAttribute($attribute[0], $attribute[1]);
                }
            } else {
                $tempEl->setAttribute($params[0], $params[1]);
            }
        }
?>

down

tschmieder at bitworks dot de ¶

9 years ago

Remember:

If you want to perform multiple actions with a new node, you may need to create a copy of it before

means: 
## Create an address to an unique memory block !
$td = $dom->createElement('td');
## Change some things in this original unique pattern
$td->setAttribute('class', 'saldo');

## clone the unique pattern to two own one's
$td1 = clone $td;
$td2 = clone $td;

## alter properties in each one
$td1->nodeValue = 'Ich bin die erste neue Node';
$td2->nodeValue = 'Ich bin die zweite neue Node';

## find the parent element
$tr = $dom->getElementById('t001-tr001');
## find the first and the last child (here only for clearity)
$first = $tr->firstChild;
$last = $tr->lastChild;

## produce the new nodes
$newtd1 = $tr->insertBefore($td1, $first);
$newtd2 = $tr->appendChild($td2);

conclusion:
YOU NEED AN ORIGINAL NEW NODE FOR EACH ACTION!

down

estill at gvtc dot com ¶

17 years ago

Note that the second parameter (value), although convenient, is non-standard. You should create elements like this instead:

<?php
$doc = new DOMDocument('1.0', 'iso-8859-1');

$root = $doc->createElement('test');
$doc->appendChild($root);

$root_text = $doc->createTextNode('This is the root element!');
$root->appendChild($root_text);

print $doc->saveXML();
?>

Or, alternatively, extend the DOMDocument class and add your own custom, convenience method to avoid intruding on the standard:

<?php
class CustomDOMDocument extends DOMDocument {
  function createElementWithText($name, $child_text) {
    // Creates an element with a child text node
    
    // @param  string  $name        element tag name
    // @param  string  $child_text  child node text
    
    // @return  object  new element
    
    $element = $this->createElement($name);
    
    $element_text = $this->createTextNode($child_text);
    $element->appendChild($element_text);
    
    return $element;
  }
}

$doc = new CustomDOMDocument('1.0', 'iso-8859-1');

$root = $doc->createElementWithText('test', 'This is the root element!');
$doc->appendChild($root);

print $doc->saveXML();
?>

Also use caution with (or avoid) the 'DOMElement->nodeValue' property. It can return some unexpected values and changing its value will replace (remove) all descendants of the element with a single text node. It's also non-standard; according to the DOM spec it should return NULL.

down

lars dot c dot magnusson at gmail dot com ¶

13 years ago

You may think insertBefore and insertAfter is a direct alternative for appendChild, this is not the case. 



<?php

$dom = new DOMDocument(); 

$dom->load($file);



$dom->appendChild($newNode); //Works fine

$dom->insertBefore($newNode, $refNode); //Will fail



$refNode->parentNode->insertBefore($newNode, $refNode); // thanx to yasindagli (first post)

?>

down

chris AT cmbuckley DOT co DOT uk ¶

15 years ago

Note that the NUL character "\0" is not in the list of invalid characters for $name, so no error is triggered, but the tag name will be truncated at the null byte:

<?php

$dom = new DOMDocument('1.0', 'utf-8');
$el = $dom->createElement('foo' . "\0" . 'bar', 'Hello World');
echo $el->tagName; // outputs "foo"

?>

down

-1

dignat at yahoo dot com ¶

6 years ago

To create an element with DomDocument and to escape ampersand in the value.

Do this:

$element = new DOMDocument('1.0', 'UTF-8');

$test = $element->createElement('text');

$test ->appendChild($element->createElement('name'))
      ->appendChild($element->createtextNode('& I am ampersand');