Solved: link and script addition on Bootstrap

Hello,

I am learning Bootstrap from W3Schools website.
When I add link and script, they recommend 'MaxCDN'.
so they add the following lines to <head> section.

<link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
 <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
 <script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>

Open in new window

However, some other sites add only

<link rel="stylesheet" href="https://cdn.rawgit.com/twbs/bootstrap/v4-dev/dist/css/bootstrap.css">

Open in new window

to the <header> section and add

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>
<script src="https://cdn.rawgit.com/twbs/bootstrap/v4-dev/dist/js/bootstrap.js"></script>

Open in new window

to <body> section.
It looks like 'CDN', not 'MaxCDN'.

And if I use 'CDN', some of stuff work that work fine with MaxCDN don't work.
For example, Glyphicons examples don't work with CDN.

What's the reason for the difference between these two?
Should I just go for 'MaxCDN'?

I am using visual Studio 2013 for coding Bootstrap examples.(in case if you know the better solution with VS 2013)