How to replace all XHTML/HTML line breaks () with new lines?

Question

I am looking for the best br2nl function. I would like to replace all instances of
and


Answer 1

If the document is well-formed (or at least well-formed-ish) you can use the DOM extension and xpath to find and replace all br elements by a \n text node.

$in = '
abc
def
ghi
jkl
';

$doc = new DOMDOcument;
$doc->loadhtml($in);
$xpath = new DOMXPath($doc);

$toBeReplaced = array();
foreach($xpath->query('//br') as $node) {
    $toBeReplaced[] = $node;
}

$linebreak = $doc->createTextNode("\n");
foreach($toBeReplaced as $node) {
    $node->parentNode->replaceChild($linebreak->cloneNode(), $node);
}

echo $doc->savehtml();

prints

abc
def
ghi
jkl

edit: shorter version with only one iteration

$in = '
abc
def
ghi
jkl
';

$doc = new DOMDOcument;
$doc->loadhtml($in);
$xpath = new DOMXPath($doc);

$linebreak = $doc->createTextNode("\n");
foreach($xpath->query('//br') as $node) {
  $node->parentNode->removeChild($node);
}

echo $doc->savehtml();