PHP - function - Adding Breaker Before Dot

function addBreakerBeforeDot($string){
    $len = strlen($string);
    $toReturn = "";
    for($c = 0; $c < $len; $c++){
        if($string[$c] == "."){
            // echo "found<br>";
            $toReturn = $toReturn."\\\\". $string[$c];

        }else{
            // echo "not found<br>";
            $toReturn .= $string[$c];
        }
    }
    return $toReturn;
}