0 1 00:00:00,510 --> 00:00:06,330 All right guys. I need this lesson we're going to be using what we learned so far about setting up a new 1 2 00:00:06,330 --> 00:00:14,520 web site with a server using Node and Express to create a really simple web site that acts as a calculator, 2 3 00:00:14,790 --> 00:00:21,570 so I can simply enter maybe two numbers, 5 and 6, and I hit calculate, and I get the result back. 3 4 00:00:21,570 --> 00:00:28,110 Now, in the process of building this, we're going to get to create our very first web application, 4 5 00:00:28,200 --> 00:00:30,260 and it's not just a web site anymore. 5 6 00:00:30,390 --> 00:00:37,710 Up till now we've only been making essentially static web sites, right, where our browser will make a 6 7 00:00:37,710 --> 00:00:44,340 request to the server and the server sends back the CSS, the HTML, the Javascript files. 7 8 00:00:44,520 --> 00:00:49,960 And if there's any Javascript code that needs to be run, it gets run on the client side, 8 9 00:00:49,980 --> 00:00:56,640 basically our user’s browser. And that Javascript gets sent to the browser and run when the user loads 9 10 00:00:56,640 --> 00:00:58,130 up the web site. 10 11 00:00:58,140 --> 00:01:02,830 Now in this lesson we're going to be making our code run server side. 11 12 00:01:02,970 --> 00:01:09,780 So when our web site makes a request to our server, it's going to execute the code and only deliver the 12 13 00:01:09,850 --> 00:01:16,370 outcome back to the user, so the user doesn't get to see any of the code and logic of our calculator. 13 14 00:01:16,370 --> 00:01:18,610 It's all done on our server. 14 15 00:01:18,840 --> 00:01:25,290 And once we grasp this concept, then we'll be able to make much faster, more complex web sites that can 15 16 00:01:25,290 --> 00:01:30,840 do computation before it even renders the web site to be delivered to the user, 16 17 00:01:31,290 --> 00:01:37,920 and we'll be able to interact with databases, and query, and search, and manipulate our databases, and create 17 18 00:01:38,190 --> 00:01:41,310 much more interesting web applications. 18 19 00:01:41,310 --> 00:01:46,610 So this is the core concept that we're going to tackle in the coming lessons of this module. 19 20 00:01:46,680 --> 00:01:48,780 But first there's a challenge. 20 21 00:01:48,780 --> 00:01:51,260 So head over to the next lesson and get started.