WebApp and include external files - sometimes I get 404 error

I have a tricky situation here.

I have an application hosted on the http://localhost/myApp

and inside the index.html file I have e.g.:

<script src="/Scripts/angular.min.js"></script>

but I get the 404 error for that file, but the file http://localhost/myApp/Scripts/angular.min.js exists.

What's more, an user can visit the app with the / char at the end of the url, in that case the problem remains.