Replace element value in DOM - php

Question

I want to save DOM tags value to exist XML, I found replace function but it is in js and I need the function in PHP
I tried save and saveXML function, but this didn't worked. I have tags in XML with colon "iaiext:auction_title". I used getElement and it's work good, next i cut title to 50 characters function work too, but how i can replace old title to this new title if i dont use path like simple_load_file. How to show in my script this path?
$dom = new DOMDocument;
$dom->load('p.xml');
$i = 0;
$tytuly = $dom->getElementsByTagName('auction_title');
foreach ($tytuly as $tytul){
$title = $tytul->nodeValue;
$end_title = doTitleCut($title);
//echo "<pre>";
//echo($end_title);
//echo "<pre>";
$i = $i+1;
}

Answer 1

In your loop, you can update a particular nodes value the same way you fetch it - with nodeValue. So in your loop, just update it each time...
$tytul->nodeValue = doTitleCut($title);
Then after your loop, you can just echo the new XML out using
echo $dom->saveXML();
or save it using
$dom->save("3.xml");

Answer 2

It is the same basic API in PHP. However browsers implement more or other parts of the API. Here are 5 revisions of the API (DOM Level 1 to 4 and DOM LS). DOM 3 added a property to read/write the text content of a node: https://www.w3.org/TR/DOM-Level-3-Core/core.html#Node3-textContent
The following example prefixes the titles:
$xml = <<<'XML'
<auctions>
<auction_title>World!</auction_title>
<auction_title>World & Universe!</auction_title>
</auctions>
XML;
$document = new DOMDocument();
$document->loadXML($xml);
$titleNodes = $document->getElementsByTagName('auction_title');
foreach ($titleNodes as $titleNode) {
$title = $titleNode->textContent;
$titleNode->textContent = 'Hello '.$title;
}
echo $document->saveXML();
Output:
<?xml version="1.0"?>
<auctions>
<auction_title>Hello World!</auction_title>
<auction_title>Hello World & Universe!</auction_title>
</auctions>
PHPs DOMNode::$nodeValue implementation does not match the W3C API definition. It behaves the same as DOMNode::$textContent for reads and does not fully escape on write.