How to limit a text by characters

I have a PHP project ( Using laravel ) and I need to show just part of an article in the view . For example this is the full content of article :

Hello World It is my First Post and I decided to share it on my personal blog .

and I wanted to show part of that in the recent posts part such this :

Hello world it is ...

I made a function but it doesn't work when I want to limit the text ( But there is no problem with short texts ) This is my function :

function limitText($text,$length=300) {
    if(strlen($text)<$length) {
        $new = $text."...";
        return $new;
    }
    $new = substr($text,0,$length);
    $new = $new."...";
    return $new; }

any idea or suggestion ?

via Dana Mirafzal