What is JavaScript used for?

JavaScript is one of the easiest languages ​​to learn and is very popular among a large number of developers. But what is the secret of such popularity and why is it generally used?

What is JavaScript?

JavaScript is a language used to provide dynamic and "intelligent" effects and processes to HTML documents. An HTML document is colloquially a "web page". Thus, it can be said that the JavaScript language is used to perform quick actions and animated effects on web pages. To order a service related to this language, you can contact javascript development.

Actions controlled by JavaScript can be displaying menus, disappearing or changing text and images, performing calculations and displaying results, displaying warning messages (for example, if data is missing from a form), and "animation effects" in general.

This language is mainly used by web programmers to provide quick responses to user actions without having to send information to the server about what the user has done and wait for a response from him (which would slow down processes). The JavaScript code is loaded in the browser at the same time as the HTML code and resides on the client (the computer where we are), so JavaScript continues to work even if the Internet connection is lost.

The main process is sending a request (which may include information such as form data) to the server, waiting for a response from the server, and receiving a response on our computer. Each process of this type consumes time, the total time can be seen from our computer side as the total process time = time to send a request + time to process a request + time to receive a response.

Even with a high browsing speed, the more processes of this type we perform, the slower web browsing will be. We can say about JavaScript that it assumes that the server responses are more complete and allows more processes to run on our computer (those processes that can be allowed on our computer without having to send requests to the server) so that the number of requests is reduced and responses needed between client and server.

JavaScript code is directly interpreted by the web browser without the need for other programs or intermediate processes. An example can help us understand the idea. Let's assume that on a web page we are asking the user to fill out a form with their data and that among the requirements for submitting the form we have a mandatory username and e-mail, it is mandatory that the name contains more than one letter and that the letter contains the @ (at) symbol.

Let's assume that the server request and response take 2 seconds, and let's see what happens with server-side process control or client-side control with JavaScript. Because the JavaScript resides on the user's computer (client), we assume that the response time implies 0 seconds of time consumption, i.e. the response is immediate.

Does this mean that we can do everything using JavaScript? Some web pages may be based on a combination of HTML with CSS and JavaScript. Even a web page can be just HTML with no CSS or JavaScript, but in professional development, these three elements usually come in along with the server-side language.

As we gain experience as programmers, we will realize that there are processes that are more suited to run on the server side, others that are better suited to run on the client side, and still others that can be run both on the server side. as well as on the client side. Also, with experience, we will learn to make decisions related to this.