What Some Common Languages Do and How They Work Together

To begin our journey about what common languages do and how they work together, 0:00 let's begin by dissecting the languages needed for a web application. 0:04 On second thought, let's begin at the drive-through. 0:09 Imagine you're at a drive-through. 0:12 You order some food through one of those giant intercom menus. 0:14 That order's sent to the kitchen where they make the food. 0:18 When the food is ready, it's put into a bag and handed to you through the window. 0:22 When you originally placed your order at the intercom, 0:26 it was like typing a URL into the browser. 0:30 The URL is sent to a web server, 0:32 the kitchen, which then produces what you asked for. 0:34 When the content is retrieved, aka your food is ready, it's placed in a bag and 0:39 handed through the window, or the front end of the website. 0:44 Just like a drive-through wouldn't put just any order through the window when you 0:49 drive up, it's the same for a website. 0:53 This is called the client server model. 0:56 The client makes a request to the server. 0:58 And the server gives back the content to the client. 1:02 Once the page has loaded, 1:05 from this point on when you send messages through the front-end, 1:06 you are sending messages to the back-end, which then returns what you asked for. 1:10 For example, maybe you forgot to ask for ketchup, so 1:16 you ask the nice lady at the front for some ketchup. 1:18 She turns around and asks the kitchen for 1:22 a packet of ketchup and hands it to you, and you walk away happy. 1:23 You can see this when you go to the Treehouse website. 1:28 When I pull up my Treehouse home page, I only see my information. 1:31 Like the points I've accrued, 1:35 my name, and the course I'm on have all come from the server. 1:37 But the layout and styling are going to look the same, whether it's you or 1:42 anyone else signing on to the Treehouse site. 1:46 The front end, or the drive-through window if you will, 1:48 uses images in the languages HTML, CSS, and JavaScript. 1:51 HTML and CSS are not programming languages exactly. 1:57 HTML is a markup language which builds the structure of the website. 2:01 And CSS is a styling language which tells the browser how 2:05 to make that structure look. 2:09 Let's leave those languages aside for now. 2:11 You'll learn a lot more about them later. 2:14 The back-end, or 2:16 the kitchen in our analogy, is made of what are called server-side languages. 2:17 And there are many different languages like PHP, Ruby, Java, and 2:22 Python to choose from. 2:27 Whether you're programming for a website or mobile app, 2:29 you're going to be dealing with a lot of the same process you just saw for the Web. 2:32 One of the big differences when developing mobile versus the Web is 2:37 the number of languages you'll need to use. 2:42 If you're programming for a mobile android device like the Moto 360 or 2:45 Samsung Galaxy, 2:49 you'll probably just be using Java to program the whole application. 2:50 If you wanted to build something for a mobile iOS device, like an iPhone or 2:55 an iPad, you'll be using Swift or Objective-C. 3:00 Hopefully now you have a better grasp of what back-end and 3:04 front-end languages are and how they work together. 3:07 In the next video we'll talk about the similarities and differences between some 3:11 of the back-end languages we discussed like Ruby, Python, PHP, and Java. 3:16