Search multiple words in a string it will return you occurred words.

strpos_multi.php

<?php

function multi_pos($text,$search) {
        $returnKey = array();
        foreach($search as $keyword)
        {
            if(isset($keyword) && $keyword !="")
            {
                if(stripos($text, $keyword))
                {
                    $returnKey[] = $keyword;
                }
            }
        }
        return $returnKey;
    }

$intro = "I am huzoor bux from PHPLift.net website.";
$search = array("am","bux","pakistan","website");
$position = multi_pos($intro, $search);
if(count($position)>0)
{
  echo implode(",", $position);
}
else
{
  echo "nothing found.";
}

?>