What is JavaScript and Where Can I Learn It?

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At the simplest level, JavaScript code is loaded behind-the-scenes when a web page is visited in nearly any modern browser. Once that page has finished loading and is displayed on screen, the JavaScript code is executed and instructs the browser what additional actions (if any) should take place. If no immediate action is to take place (such as placing the text cursor in a search box), then typically the JavaScript code simply sits idle, waiting for a particular event to occur, at which point the JavaScript code fires and performs a necessary action.

For example, when filling out the password box in a registration form, JavaScript will often be waiting for the moment when the user begins typing characters into the password box. In the event that the user types a special character that this particular web page doesn’t allow as part of a valid password, the JavaScript code will immediately notice this issue and pop up a small text alert near the password field, informing the user of this issue.

While adept users may consider or even recognize that this verification process of ensuring the password field contains valid characters can be performed by the server (the remote computer hosting the website), this illustrates the fundamental power of JavaScript as a technology: JavaScript can perform tasks immediately, directly on the device the user is interacting with, without the delays normally necessary when sending and receiving information from a web site.

Why is JavaScript Essential?

Aside from the power and control that implementing JavaScript into a website has for the company behind that site, it’s also critical to understand just how vital JavaScript as a technology is, both at present and well down the road for the foreseeable future. Having a solid grasp of what JavaScript is, and perhaps even how to begin coding and working with it, are among the most crucial skills anyone interested in web technologies or development can gain.

A multitude of technologies have sprung up in recent years that heavily focus on utilizing the power of JavaScript.

Node.js, a server-side JavaScript library built using Google’s V8 JavaScript engine, is among the most dominant of these technologies. Node.js is powerful and robust enough that, over the last few years, a great number of big name companies have migrated their services from older technologies to Node.js, including Netflix, PayPal, and Uber. What makes Node.js so interesting is that, unlike most implementations of JavaScript in the past, Node.js allows JavaScript to be the backbone language that handles everything on the server itself, rather than merely managing interactions only on the user’s computer. Not only is JavaScript widely used by massive companies and services, in fact all signs indicate that it is among the most popular programming languages used day-to-day by developers worldwide.

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