Uncaught exception 'DOMException' with message 'Hierarchy Request Error'

Question

I'm getting error while replacing or adding a child into a node.

Required is :

I want to change this to..

<?xml version="1.0"?>
<contacts>
  <person>Adam</person>
  <person>Eva</person>
  <person>John</person>
  <person>Thomas</person>
</contacts>

like this

<?xml version="1.0"?>
<contacts>
  <person>Adam</person>
  <p>
      <person>Eva</person>
  </p>
  <person>John</person>
  <person>Thomas</person>
</contacts>

error is

Fatal error: Uncaught exception 'DOMException' with message 'Hierarchy Request Error'

my code is

function changeTagName($changeble) {
    for ($index = 0; $index < count($changeble); $index++) {
        $new = $xmlDoc->createElement("p");
        $new ->setAttribute("channel", "wp.com");
        $new ->appendChild($changeble[$index]);
        $old = $changeble[$index];
        $result = $old->parentNode->replaceChild($new , $old);
    }
}

Answer 1

The error Hierarchy Request Error with DOMDocument in PHP means that you are trying to move a node into itself. Compare this with the snake in the following picture:

Similar this is with your node. You move the node into itself. That means, the moment you want to replace the person with the paragraph, the person is already a children of the paragraph.

The appendChild() method effectively already moves the person out of the DOM tree, it is not part any longer:

$para = $doc->createElement("p");
$para->setAttribute('attr', 'value');
$para->appendChild($person);

<?xml version="1.0"?>
<contacts>
  <person>Adam</person>

  <person>John</person>
  <person>Thomas</person>
</contacts>

Eva is already gone. Its parentNode is the paragraph already.

So Instead you first want to replace and then append the child:

$para = $doc->createElement("p");
$para->setAttribute('attr', 'value');
$person = $person->parentNode->replaceChild($para, $person);
$para->appendChild($person);

<?xml version="1.0"?>
<contacts>
  <person>Adam</person>
  <p attr="value"><person>Eva</person></p>
  <person>John</person>
  <person>Thomas</person>
</contacts>

Now everything is fine.