Typed.Js doesn't show up? Smartbackspacing doesn't work?

I'm a complete beginner in creating websites, and that's why this problem may be dumb, but just ignore that fact and help me please: My Problem is that typed.js doesn't work(Like i said i am complete beginner) for some reason, please try to fix that. Code :

    <!-- jQuery (necessary for Bootstrap's JavaScript plugins) --> 
<script src="js/jquery-1.11.3.min.js"></script>

<!-- Include all compiled plugins (below), or include individual files as needed --> 
<script src="js/bootstrap.js"></script>
<script src="js/typed.js"></script>
<script src="js/particles.js"></script>
<script src="js/app.js"></script>
    <script>
    var options = {
    strings: ["HI im am cool", "HI im not cool"],
    typeSpeed: 40

    }

    var typed = new Typed(".typing", options);
    });

    </script>