Hi everybody. Today I'm going to introduce you to the JavaScript programming language. JavaScript has a lot of uses, but we're really gonna focus on how we can use JavaScript to add interactivity to your web design pages. So while I'm assuming that you're new to programming, there is an expectation that you know HTML 5 and CSS. If you don't, you're really gonna wanna go back and review those two areas because everything we with JavaScript in this class is based on web programming. So let's get started. If you've done HTML, if you've done CSS, you haven't necessarily done what we call real programming, at least not what us computer scientists call real programming. Instead, we're going to be talking in JavaScript about really definite data manipulation, and in order to do that, there are a few things you need to learn how to do. The first is, you wanna learn how to store variables. You're gonna wanna learn how to set decision points, you're gonna be looping and writing functions, you're also going to be really getting in-depth with how you can get data from the browser. So did you know that every time you load a web page, you can actually get back the title of the page, the URL of your page, a lot of different information that you know is there, but you can't always see at first glance? The other thing we can do, which is really where it gets a little bit more exciting, is that we can manipulate the DOM that the browsers use to create webpages. So the DOM is the Document Object Model, it's what builds up a webpage. If you're a little fuzzy, it's been a little while, don't worry. We're gonna review the DOM in a future lecture. So let's start with variables. In computer science, we use variables in order to store information. Your program isn't going to be very exciting if you ask somebody their name and then you can't actually use that name later on. So you're gonna find out how to get information from the user, and then store it so you can use it later. We're also going to add decision points. Things are much more interesting when they don't do the same thing every single time. So we're gonna write a little bit of code that can help the program decide in some cases I wanna do this and in other cases, I wanna do that. We call this decision points. We can also do looping. Looping is really powerful. As your programs get bigger, there's certain things you'll wanna do over and over again, but you really don't wanna write code over and over and over again. So in computer science, we use something called looping to control the program and say, see that little bit of code over there? We wanna do that five times, or ten times, or we wanna keep doing it until the human does what we want them to do. Otherwise, you sometimes have to decide at run time how many times you want to run some code. So if you know that you want someone to do something five times, you can be very specific about it. Programming gives you so much flexibility in how you want your code to run. Next in this course we're gonna talk about functions. Functions are one, are a way for you to reuse your code multiple times, but you only have to write it once. The other really great things about functions is that other people can write code and you can use it, and you don't even need to know how it works all you need to know is, what did you call your function? Great. I wanna use that. Finally, we're gonna talk about manipulating the dominant class. JavaScript can actually go through your web page and search and find certain elements. It can add new elements. It can delete other elements from the DOM. So think about when you're filling out a form on a web page with your credit card information. There's always these little buttons that you can click that can say use the same billing address for shipping. Things like this can make your page much more usable. You can also react to mouse clicks, page reloads, and other actions that the user might have. So this is where it really gets fun. We're gonna start with the basics, the variables, the loopings, and then we're gonna have fun manipulating the DOM. So a major component of learning any new programming language, or I guess, really any language at all, is that the key is practice and repetition. The other thing that you really need to understand, and I'm actually hoping that you'll embrace, is that you need to expect that you're going to make mistakes. If you aren't making mistakes constantly, you aren't really learning in this class. So join us, we're going to do a lot of fun stuff. But I promise, I'm gonna go slow, explain what I'm doing step by step, so that you can come along with me and start adding some interactivity to your pages with JavaScript.
