html - getting all values from h1 tags using php

I want to receive an array that contains all the h1 tag values from a text

Example, if this where the given input string:

hello

random text
title number two!

I need to receive an array containing this:

titles[0] = 'hello',
titles[1] = 'title number two!'

I already figured out how to get the first h1 value of the string but I need all the values of all the h1 tags in the given string.

I'm currently using this to receive the first tag:

function getTextBetweenTags($string, $tagname) 
 {
  $pattern = "/<$tagname ?.*>(.*)<\/$tagname>/";
  preg_match($pattern, $string, $matches);
  return $matches[1];
 }

I pass it the string I want to be parsed and as $tagname I put in "h1".
I didn't write it myself though, I've been trying to edit the code to do what I want it to but nothing really works.

I was hoping someone could help me out.

Thanks in advance.

Answer

you could use simplehtmldom:

function getTextBetweenTags($string, $tagname) {
    // Create DOM from string
    $html = str_get_html($string);

    $titles = array();
    // Find all tags 
    foreach($html->find($tagname) as $element) {
        $titles[] = $element->plaintext;
    }

}