With a basic understanding of JavaScript, you can manipulate the various interactive features of your website to perform a wide range of actions. If you want to have complete control over the design and function of your website, you should know at least some of the coding involved with JavaScript. The types of things that you can do with JavaScript are practically limitless. This programming language can provide you with the tools needed to:.
No matter which programming language you want to learn, there are free resources all over the internet that will provide you with what you need to understand the basics of the language in question. The best resources available to you include free online courses that will teach you the basics of the language in an organized and structured manner. If you want to learn how to effectively use HTML for your website, check out this course at Codecademy. By the end of the 9-hour course, you should be able to use HTML on your website without running into many issues.
The same website also offers free tutorials for CSS and JavaScript , both of which have proven to be very popular and highly effective. While the HTML and CSS courses have five and six lessons respectively for you to take, the JavaScript course is even more robust and includes 14 lessons with 30 hours of coursework. Overall, you have more control over how your website looks, feels, and performs when you have some knowledge of these programming languages.
The web browser receives the JavaScript code in its original text form and runs the script from that. From a technical standpoint, most modern JavaScript interpreters actually use a technique called just-in-time compiling to improve performance; the JavaScript source code gets compiled into a faster, binary format while the script is being used, so that it can be run as quickly as possible.
However, JavaScript is still considered an interpreted language, since the compilation is handled at run time, rather than ahead of time. You might also hear the terms server-side and client-side code, especially in the context of web development.
Client-side code is code that is run on the user's computer — when a web page is viewed, the page's client-side code is downloaded, then run and displayed by the browser. In this module we are explicitly talking about client-side JavaScript. Server-side code on the other hand is run on the server, then its results are downloaded and displayed in the browser. NET and JavaScript can also be used as a server-side language, for example in the popular Node.
Server-side code dynamically generates new content on the server, e. The meaning is slightly different in the two contexts, but related, and both approaches server-side and client-side usually work together. A web page with no dynamically updating content is referred to as static — it just shows the same content all the time.
Let's learn how this works. Note: If your example doesn't seem to work, go through the steps again and check that you did everything right. Did you save your local copy of the starting code as a. Did you enter the JavaScript exactly as shown? JavaScript is case sensitive, and very fussy, so you need to enter the syntax exactly as shown, otherwise it may not work.
Note: You can see this version on GitHub as apply-javascript-internal. This works great, but what if we wanted to put our JavaScript in an external file? Let's explore this now. Note: You can see this version on GitHub as apply-javascript-external. It might look something like this:. Please don't do this, however. In this case the addEventListener function allows you to select all the buttons using one instruction. The code we used above to serve this purpose looks like this:.
This might be a bit longer than the onclick attribute, but it will work for all buttons — no matter how many are on the page, nor how many are added or removed.
The JavaScript does not need to be changed. Note: Try editing your version of apply-javascript. When you reload, you should find that all of the buttons when clicked will create a paragraph. Neat, huh? There are a number of issues involved with getting scripts to load at the right time. Nothing is as simple as it seems! A common problem is that all the HTML on a page is loaded in the order in which it appears.
If you are using JavaScript to manipulate elements on the page or more accurately, the Document Object Model , your code won't work if the JavaScript is loaded and parsed before the HTML you are trying to do something to. In the above code examples, in the internal and external examples the JavaScript is loaded and run in the head of the document, before the HTML body is parsed. It's an essential skill for any web professional.
It's the starting point for anyone learning how to create content for the web. And, luckily for us, it's surprisingly easy to learn.
Let me show you what I mean. Take a look at the article below. If I were to ask you to label the types of content on the page, you'd probably do pretty well: There's the header at the top, then a subheader below it, the body text, and some images at the bottom followed by a few more bits of text. Markup languages work in the same way as you just did when you labeled those content types, except they use code to do it -- specifically, they use HTML tags, also known as "elements.
Every web page is made up of a bunch of these HTML tags denoting each type of content on the page. Each type of content on the page is "wrapped" in, i. For example, the words you're reading right now are part of a paragraph.
The "tag" part is denoted by open brackets, and the letter "p" tells the computer that we're opening a paragraph instead of some other type of content. Once a tag has been opened, all of the content that follows is assumed to be part of that tag until you "close" the tag. Notice that closing tags look exactly the same as opening tags, except there is a forward slash after the left angle bracket.
Here's an example:. Using HTML, you can add headings, format paragraphs, control line breaks, make lists, emphasize text, create special characters, insert images, create links, build tables, control some styling, and much more.
This programming language dictates how the HTML elements of a website should actually appear on the frontend of the page. HTML provides the raw tools needed to structure content on a website. CSS, on the other hand, helps to style this content so it appears to the user the way it was intended to be seen. These languages are kept separate to ensure websites are built correctly before they're reformatted. Those slick colors, interesting fonts, and background images?
All thanks to CSS. This language affects the entire mood and tone of a web page, making it an incredibly powerful tool -- and an important skill for web developers to learn. It's also what allows websites to adapt to different screen sizes and device types. To show you what CSS does to a website, look at the following two screenshots.
Notice all the content is still there, but the visual styling isn't. This is what you might see if the style sheet doesn't load on the website, for whatever reason.
Now, here's what the same web page looks like with CSS added. Put simply, CSS is a list of rules that can assign different properties to HTML tags, either specified to single tags, multiple tags, an entire document, or multiple documents. It exists because, as design elements like fonts and colors were developed, web designers had a lot of trouble adapting HTML to these new features. You see, HTML, developed back in , was not really intended to show any physical formatting information.
It was originally meant only to define a document's structural content, like headers versus paragraphs. So, what exactly does CSS stand for? It stands for Cascading Style Sheets -- and "style sheet" refers to the document itself.
Ever web browser has a default style sheet, so every web page out there is affected by at least one style sheet -- the default style sheet of whatever browser the web page visitor is using -- regardless whether or not the web designer applies any styles. Print [2]Crockford, Douglas. JavaScript: The Good Parts. User assumes all risk of use, damage, or injury.
You agree that we have no liability for any damages. What is HTML? What is JavaScript? Client-side vs. Server-side — HTML is rendered from the web server which means the markup code is processed by the server before it is sent to the client browser.
JavaScript vs. Author Recent Posts. Sagar Khillar. He has that urge to research on versatile topics and develop high-quality content to make it the best read. Thanks to his passion for writing, he has over 7 years of professional experience in writing and editing services across a wide variety of print and electronic platforms.
Outside his professional life, Sagar loves to connect with people from different cultures and origin. You can say he is curious by nature.
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