JavaScript

JavaScript is the language a web browser already understands, so nothing has to be installed before it works. That is why clicking a button can change one part of a page while the rest stays exactly where it was. The cart total that jumps the moment you add a second item is one small example. So is the map that slides under your finger, and so is the form that tells you the phone number is wrong before you press send. All of it is the same language, doing small jobs inside the page while you look at it.

It started as a small thing, because it was made in 1995 for exactly those little movements and did nothing else for years. Then people took the same language and ran it on the server, and later put it inside phone apps and desktop programs as well. That means one team can now write the screen the customer sees and the engine behind it without switching languages. It saves real money on a project, because you hire one group of people instead of two. Its reach, not its beauty, is the reason more software is written in JavaScript than in anything else.

Here is the part that surprises owners: everything written in JavaScript is sent to the visitor's browser, so they can read and change it. Open any page, press F12, and the code is sitting right there. A discount rule that lives only in JavaScript is therefore a suggestion rather than a rule, because someone can edit the price in their own browser and then press buy. So the server has to check that price again on its own before it takes any money. That is one of the first things Linkysoft tests when it takes over a shop or a booking site that is already running, and one of the most common findings in a security review.

The second surprise is speed, because a page full of JavaScript feels quick on a new phone on office wifi. On a five-year-old handset running on mobile data, the same page turns slow. That older phone is the one people actually shop with, so ask any supplier to open the site on a cheap Android before you sign anything. Linkysoft builds both web applications and the mobile apps that sit beside them, and we test on old handsets on purpose. That is where the sale quietly gets lost.