PHP Find all occurrences of a substring in a string

Question

I need to parse an HTML document and to find all occurrences of string asdf in it.

I currently have the HTML loaded into a string variable. I would just

Answer 1

function getocurence($chaine,$rechercher)
        {
            $lastPos = 0;
            $positions = array();
            while (($lastPos = strpos($chaine, $rechercher, $lastPos))!== false)
            {
                $positions[] = $lastPos;
                $lastPos = $lastPos + strlen($rechercher);
            }
            return $positions;
        }