NOTE This file was generated by Descript 1 00:00:00,690 --> 00:00:04,680 In this lecture, we're going to talk about HTML, CSS, and JavaScript. 2 00:00:04,710 --> 00:00:08,310 Particularly about what each of these languages is for and how we 3 00:00:08,310 --> 00:00:10,530 use them in modern web development. 4 00:00:11,180 --> 00:00:14,430 HTML is a markup language, which means it's for annotating 5 00:00:14,430 --> 00:00:16,050 the content of a document. 6 00:00:16,530 --> 00:00:19,770 Since the introduction of HTML 5, annotations have had a very 7 00:00:19,770 --> 00:00:23,490 specific purpose, which is to describe the structure and the 8 00:00:23,490 --> 00:00:25,170 meaning of the pages content. 9 00:00:25,755 --> 00:00:29,715 And this is in stark contrast to older versions of HTML and many other 10 00:00:29,715 --> 00:00:33,254 markup languages, which are concerned with the appearance of the content. 11 00:00:33,795 --> 00:00:37,485 For example, Markdown, which is commonly used by instant messaging services and 12 00:00:37,485 --> 00:00:39,945 forums to change the appearance of text. 13 00:00:40,575 --> 00:00:45,495 Our HTML documents are going to contain the content of our pages, augmented by 14 00:00:45,495 --> 00:00:47,955 annotations in the form of HTML tags. 15 00:00:48,465 --> 00:00:51,675 The content includes things like images, videos, forms and 16 00:00:51,675 --> 00:00:53,205 of course the text content. 17 00:00:53,505 --> 00:00:55,575 The tags are there to describe that content. 18 00:00:56,455 --> 00:00:59,715 We'll be covering HTML in a lot of detail in the next section. 19 00:01:00,480 --> 00:01:03,780 CSS is used to describe the presentation of a document. 20 00:01:03,780 --> 00:01:07,470 In other words it's for changing how things look on our web pages. 21 00:01:08,310 --> 00:01:12,600 Modern CSS is extremely versatile and powerful, and we can even create 22 00:01:12,600 --> 00:01:15,030 complex animations just with CSS. 23 00:01:15,539 --> 00:01:19,740 CSS uses the system of selectors which describe what we should change the 24 00:01:19,740 --> 00:01:24,690 appearance of, and property definitions which describe how the appearance of 25 00:01:24,690 --> 00:01:26,400 the selected things should change. 26 00:01:27,390 --> 00:01:29,895 We'll be covering CSS in section five. 27 00:01:30,855 --> 00:01:33,495 JavaScript is a fully fledged programming language which is 28 00:01:33,495 --> 00:01:35,835 supported by every major browser. 29 00:01:36,075 --> 00:01:37,455 And that makes it unique. 30 00:01:37,965 --> 00:01:41,595 We can't just execute our Python code in the browser for example. 31 00:01:41,625 --> 00:01:44,235 The browser just doesn't understand Python. 32 00:01:44,955 --> 00:01:49,155 JavaScript is primarily used for handling complex user interactions and 33 00:01:49,155 --> 00:01:53,505 manipulating the other code that exists on the page, such as the HTML code. 34 00:01:53,895 --> 00:01:57,405 You can do things like add or remove elements or make requests to a 35 00:01:57,405 --> 00:01:59,625 server without reloading the page. 36 00:02:00,795 --> 00:02:04,485 There's been something of a trend recently to try to do everything with JavaScript, 37 00:02:04,725 --> 00:02:08,985 but I actually suggest you avoid JavaScript as much as possible for now. 38 00:02:09,345 --> 00:02:12,765 There are definitely legitimate use cases for JavaScript, but it's 39 00:02:12,765 --> 00:02:17,295 important that we don't rely on it too heavily for core site functionality. 40 00:02:17,775 --> 00:02:20,685 Many people browse the web with JavaScript disabled in their browser. 41 00:02:21,075 --> 00:02:24,495 They might do this for security reasons, because JavaScript is really powerful 42 00:02:24,675 --> 00:02:28,635 and can be used maliciously, but they might also do it for performance reasons. 43 00:02:28,845 --> 00:02:32,595 Or as we've learned, their browser may just not support the JavaScript 44 00:02:32,595 --> 00:02:34,365 features you've used on your page. 45 00:02:34,905 --> 00:02:37,815 If you rely too strongly on JavaScript, you may prevent some of 46 00:02:37,815 --> 00:02:39,705 these users from accessing your site. 47 00:02:39,975 --> 00:02:43,155 And that may be totally fine, but it's definitely something to think about. 48 00:02:44,415 --> 00:02:48,195 In addition to that, being able to design and write beautiful, simple, 49 00:02:48,195 --> 00:02:53,025 and usable sites with nothing but HTML and CSS is a great skill to have. 50 00:02:53,985 --> 00:02:56,955 Thank you guys for watching this video and I'll see you in the next one.