Close open HTML tags in a string
Here is a function i've used before, which works pretty well:
function closetags($html) {
preg_match_all('#<(?!meta|img|br|hr|input\b)\b([a-z]+)(?: .*)?(?<![/|/ ])>#iU', $html, $result);
$openedtags = $result[1];
preg_match_all('#</([a-z]+)>#iU', $html, $result);
$closedtags = $result[1];
$len_opened = count($openedtags);
if (count($closedtags) == $len_opened) {
return $html;
}
$openedtags = array_reverse($openedtags);
for ($i=0; $i < $len_opened; $i++) {
if (!in_array($openedtags[$i], $closedtags)) {
$html .= '</'.$openedtags[$i].'>';
} else {
unset($closedtags[array_search($openedtags[$i], $closedtags)]);
}
}
return $html;
}
Personally though, I would not do it using regexp but a library such as Tidy. This would be something like the following:
$str = '<p>This is some text and here is a <strong>bold text then the post stop here....</p>';
$tidy = new Tidy();
$clean = $tidy->repairString($str, array(
'output-xml' => true,
'input-xml' => true
));
echo $clean;
This PHP method always worked for me. It will close all un-closed HTML tags.
function closetags($html) {
preg_match_all('#<([a-z]+)(?: .*)?(?<![/|/ ])>#iU', $html, $result);
$openedtags = $result[1];
preg_match_all('#</([a-z]+)>#iU', $html, $result);
$closedtags = $result[1];
$len_opened = count($openedtags);
if (count($closedtags) == $len_opened) {
return $html;
}
$openedtags = array_reverse($openedtags);
for ($i=0; $i < $len_opened; $i++) {
if (!in_array($openedtags[$i], $closedtags)){
$html .= '</'.$openedtags[$i].'>';
} else {
unset($closedtags[array_search($openedtags[$i], $closedtags)]);
}
}
return $html;
}
And what about using PHP's native DOMDocument class? It inherently parses HTML and corrects syntax errors... E.g.:
$fragment = "<article><h3>Title</h3><p>Unclosed";
$doc = new DOMDocument();
$doc->loadHTML($fragment);
$correctFragment = $doc->getElementsByTagName('body')->item(0)->C14N();
echo $correctFragment;
However, there are several disadvantages of this approach.
Firstly, it wraps the original fragment within the <body>
tag. You can get rid of it easily by something like (preg_)replace() or by substituting the ...->C14N()
function by some custom innerHTML() function, as suggested for example at http://php.net/manual/en/book.dom.php#89718.
The second pitfall is that PHP throws an 'invalid tag in Entity' warning if HTML5 or custom tags are used (nevertheless, it will still proceed correctly).
A small modification to the original answer...while the original answer stripped tags correctly. I found that during my truncation, I could end up with chopped up tags. For example:
This text has some <b>in it</b>
Truncating at character 21 results in:
This text has some <
The following code, builds on the next best answer and fixes this.
function truncateHTML($html, $length)
{
$truncatedText = substr($html, $length);
$pos = strpos($truncatedText, ">");
if($pos !== false)
{
$html = substr($html, 0,$length + $pos + 1);
}
else
{
$html = substr($html, 0,$length);
}
preg_match_all('#<(?!meta|img|br|hr|input\b)\b([a-z]+)(?: .*)?(?<![/|/ ])>#iU', $html, $result);
$openedtags = $result[1];
preg_match_all('#</([a-z]+)>#iU', $html, $result);
$closedtags = $result[1];
$len_opened = count($openedtags);
if (count($closedtags) == $len_opened)
{
return $html;
}
$openedtags = array_reverse($openedtags);
for ($i=0; $i < $len_opened; $i++)
{
if (!in_array($openedtags[$i], $closedtags))
{
$html .= '</'.$openedtags[$i].'>';
}
else
{
unset($closedtags[array_search($openedtags[$i], $closedtags)]);
}
}
return $html;
}
$str = "This text has <b>bold</b> in it</b>";
print "Test 1 - Truncate with no tag: " . truncateHTML($str, 5) . "<br>\n";
print "Test 2 - Truncate at start of tag: " . truncateHTML($str, 20) . "<br>\n";
print "Test 3 - Truncate in the middle of a tag: " . truncateHTML($str, 16) . "<br>\n";
print "Test 4: - Truncate with less text: " . truncateHTML($str, 300) . "<br>\n";
Hope it helps someone out there.