JavaScript Cheat Sheet + PDF

JavaScript. We’ve all heard of it, but understanding anything beyond the name is not a simple task.

That’s why you’re here:

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It’s time to brush up on your JavaScript. 

Since you’re here to learn how to create a website or make a blog from scratch, I’m going to show you what this Javascript programming language is all about, but more than that, I’m going to give you complete and unrestricted access to a cheat sheet that will give you the edge you’ve been looking for.

Ready? Here’s what we’re covering:

  • JavaScript: What The Heck is That?
  • The Greatest JavaScript Cheat Sheet This Side of The Internet
  • Frequently Asked Questions About JavaScript
  • The Power (and Limitations) Of JavaScript

JavaScript: What The Heck is That?

JavaScript is a programming language that’s used to add interactivity to web pages. It runs on the computer of your visitors and doesn’t require anything annoying like constant downloads to work properly. Examples are things like polls and quizzes.

Here are some quick facts about JavaScript:

  • It’s a lightweight, interpreted programming language
  • Designed for creating network-centric applications
  • Complementary to and integrated with Java and HTML
  • Open and cross-platform
  • Originally known as LiveScript, but Netscape changed it to JavaScript

The Greatest JavaScript Cheat Sheet This Side of The Internet

handy javascript cheat sheet

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Frequently Asked Questions About JavaScript

Here’s one:

Are JavaScript and Java the same thing? 

Something we need to get out of the way right now, is that Java and JavaScript are not the same thing. The names are similar, yes, but that’s about the only similarity.

Now that we’ve covered that small, but important detail, we can dig deeper into JavaScript as a whole.

What do users need to utilize JavaScript on websites they visit? 

This programming language is built into most major web browsers like Internet Explorer, Firefox, and Safari.

Users who visit your site need to have JavaScript support on their browsers, and it must be enabled (it is by default), for everything you’ve written to function properly.

Can I only use JavaScript if I know how to write it? 

Here’s an interesting fact:

You don’t need an intimate knowledge of JavaScript to use it!

That’s right, there are plenty of pre-written JavaScripts that people have made available for new users to just plug right into their web pages. You just have to know where to place the scripts, and you’re good to go.

Is there a special program for writing JavaScript? 

Now, if you’re interested in writing JavaScript, you’ll just need a plain text editor, like Notepad to get started. If you’re using an editor to write your code, the job gets even easier, because these programs will color-code the text to help you find mistakes quicker.

Can I use HTML instead of JavaScript? 

No, JavaScript and HTML are two different beasts, but you can check out our HTML5 cheat sheet if you’re in need of help with that programming language. You see, HTML is used as a markup language for defining elements of static web pages, while JavaScript is a programming language that’s used for dynamic tasks.

Can I use PHP or some other server-side language instead? 

This is a tough one to answer because it is possible. You can only use an alternate language if it runs before the page loads. Anything that runs after the page has loaded must be JavaScript. It’s the only language supported by all web browsers that supports client-side scripting.

Does JavaScript go in the same file as HTML? 

You can do it this way, but it’s more easily used across multiple pages if you place it in separate files. You can use a .JS extension to help differentiate them. You can link your JavaScript to HTML by inserting a <script> tag.

You can add this same script to several pages by using the correct tags into each of the pages to establish a link.

What is Client-side JavaScript?

Client-side JavaScript is the most commonly used form of this language. The script should be added to, or referenced in HTML documents for the code to be properly understood and interpreted by the browser.

A web page can be made using static HTML but can include programs that interact with users and create dynamic HTML content. The client-side JavaScript mechanism allows you to do a lot more than you could with traditional CGI server-side scripts.

For example, JavaScript can be used to check if the user has entered a valid email address in a form field. Handy stuff!

The Advantages (And Limitations) Of JavaScript 

JavaScript has a lot going for it, but like anything, it’s not perfect. Let’s take a look at what it does really well, and where you may need something else to get the job done. Understanding these limitations is key to properly utilizing the language.

The Advantages of JavaScript

  • Less Server Interaction – You can ensure that user input is valid before sending it to the server. This saves traffic and reduces the load on the server as a whole.
  • Immediate Feedback – Users can immediately find out if they’ve missed an entry, as opposed to waiting for a page to load.
  • More Interactivity – You can use JavaScript to create interfaces that react to users when they hover over them with a mouse or trigger them via a keyboard.
  • Richer User Interface – You can use JavaScript to include items like drag-and-drop components and sliders to improve the quality of your interfaces.

As you can see, JavaScript does a lot of things really well, but let’s look at the limitations before we part. These are some of the features that some people may find lacking.

JavaScript’s Limitation

  • Client-side JavaScript doesn’t allow reading or writing of files. This was chosen for security reasons.
  • JavaScript cannot be used for networking applications because there’s no support available for this.
  • JavaScript doesn’t have support for multi-threading or multiprocessor capabilities.

Final Thoughts

JavaScript is a powerful tool for making your web pages more interactive, engaging, and better suited to the user experience. With this knowledge and cheat sheet, you’ll have everything you need to create dynamic and exciting web pages.

How do you use JavaScript? Let us know in the comments!