正则表达式剥离特定HTML标记内的字符串

Question

I'm trying to strip out a string, which occurs only once on a page obtained using cURL. Example:

<h3 class=" ">STRING IN QUESTION</h3>

or

<h3 class="active">STRING IN QUESTION</h3>

or

<h3 class=" active">STRING IN QUESTION</h3>

I would like to do this using preg_match, unless it can be accomplished with a less resource-intensive method.

Here is the regex I'm using, which is producing zero results:

<h3\sclass="\s">(.*?)</h3>

EDIT:

Here is the actual code (an actual URL used here in place of dynamic one) -- discovered that when pulled via cURL, the class attribute does not exist, but still does not work as shown:

$ch = curl_init ("URL IN QUESTION"); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$page = curl_exec($ch);

preg_match('<h3>(.*?)</h3>', $page, $match);

print_r($match);

Prints Nothing

Answer 1

This does the trick:

$str='<h3 class=" ">STRING IN QUESTION</h3>';
preg_match('/<h3.*?>(.*?)<\/h3>/',$str,$match);
print_r($match);

Output:

Array
(
    [0] => <h3 class=" ">STRING IN QUESTION</h3>
    [1] => STRING IN QUESTION
)

Explanation:

<h3.*?> # Match h3 tags (non-greedy)
(.*?)   # Match everything after tag (non-greedy, captured)     
<\/h3>  # Match closing tag - Note the escaped forward slash!

However that URL contains no <h3> tags, it does contain a <h1> tag however and to match it you would need to make the regex match newlines with a trailing s

preg_match('/<h1.*?>(.*?)<\\/h1>/s',$page,$match);

Output:

Array
(
    [0] => <h1 class="">
<span class="pageTitle ">Braman Motorcars</span>
</h1>
    [1] => 
<span class="pageTitle ">Braman Motorcars</span>

)

Answer 2

Maybe:

<h3\s+class="\s*(active)?">(.*?)</h3>

and then use the \\1 to retrieve "active" or "" and \\2 for "String in question"

I've never done any php, but maybe this would work?:

$result = "not found"
if (preg_match('#<h3\s+class="\s*(active)?">(.*?)</h3>#', $page, $match))
{
    $result = $match;
}
print_r($result)

Answer 3

Try with:

preg_match('#<h3\s?class="\s?(active)?">(.+)</h3>#', $yourString, $match);

Remember, in your regex you must always provide a delimiter .