Full stack development program of small development of (a)

Full stack development program of small development of (a)

Full stack development, is the first time I learned, first of all to tell you about the basic situation is as follows:
(a) the purpose of the whole stack development: the offline applets become online applet.
(B) the service-side development concept: "I allow you into my world, but does not allow you to walk around in my world."
Content (c)

(1) web server role (HTTP: Hypertext Transfer Protocol), to explain personally feel that this picture is relatively clear:

(2) there is use to Express, the following is a brief introduction Express:

(3) determine the conditions for call routing middleware, express routes and middleware is a combination of

see here a little bit foggy, say below several concepts, one is Express, the other is the NPM