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Importing one DOMDocument into another

I am attempting to merge 2 html documents, A and B. A should basically integrate B. Consider the following code:

$domA = new DOMDocument();
$domA->loadHTMLFile('foo/bar/A.html');

$domB = new DOMDocument();
$domB->loadHTMLFile('foo/bar/B.html');

$elementToReplace = /*some element in $domA*/;

$domA->importNode($domB, true); /*<-- error occuring here: Node Type Not Supported*/
$domA->replaceChild($domB, $elementToReplace);

I don't really understand why importNode wouldn't work on a DOMDocument object as it is a subclass of DOMNode in PHP, which the importNode()-function requires as an argument. (importNode(), DOMDocument)

I have already been looking at some of the similar questions but wasn't able to find anything that would have helped me in this situation.

Solution

  • You are trying to use the DOMDocument $domB as the imported node, instead you need to import the content - $domB->documentElement is the root element.

    A quick example (with comments) as to how to use it...

    $domA = new DOMDocument();
$domA->loadHTMLFile('a.html');
$domB = new DOMDocument();
$domB->loadHTMLFile('b.html');

// Find the point to replace with new content
$elementToReplace = $domA->getElementById("InsertHere");

// Import the base of the new document as $newNode
$newNode = $domA->importNode($domB->documentElement, true);
// Using the element to replace, move up a level and replace
$elementToReplace->parentNode->replaceChild($newNode, $elementToReplace);
echo $domA->saveHTML();

    with a.html...

    <html>
<head></head>
<body>
  <div id="InsertHere" />
</body>
</html>

    and b.html

    <div>New content to insert</div>

    Will give ...

    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
<html><head></head><body>
  <html><body><div>New content to insert</div></body></html>
</body></html>

    Note as you are using loadHTMLFile() it has wrapped even the small fragment of HTML into a full page. If instead you use...

    $domB->load('b.html');

    the result is...

    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
<html><head></head><body>
  <div>New content to insert</div>
</body></html>

    Note that using load() though is loading XML and is much less forgiving of the document structure than it's loadHTML() counterpart.