url_detect.php

<?php
#######################################################################
## URL DOESN'T REQUIRE http:// OR https://
## WILL DETECT IF LINK FORMAT IS CORRECT AND THEN ADD http:// BY ITSELF
#######################################################################

//The text to look for the link
$text = "The text you want to filter goes here. www.google.com and www.facebook.com";

//Call the function
echo turnUrlIntoHyperlink($text);

function turnUrlIntoHyperlink($string){

	//The Regular Expression filter
	$reg_exUrl = "/(?i)\b((?:https?:\/\/|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}\/)(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:'\".,<>?«»“”‘’]))/";

	// Check if there is a url in the text
	if(preg_match_all($reg_exUrl, $string, $url)) {

        // Loop through all matches
        foreach($url[0] as $newLinks){
            if(strstr( $newLinks, ":" ) === false){
				$link = 'http://'.$newLinks;
			}else{
				$link = $newLinks;
			}

            // Create Search and Replace strings
            $search  = $newLinks;
            $replace = '<a href="'.$link.'" title="'.$newLinks.'" target="_blank">'.$link.'</a>';
            $string = str_replace($search, $replace, $string);
        }
	}

    //Return result
	return $string;
}
?>