The three standard web technologies
HTML is short for Hypertext Markup Language, and it is used to provide structure for the content you see on any web page. For instance, it highlights new paragraphs, headings, or tables, and it can help you to embed items or files on any web page you’re developing.
Cascading style sheets provide the rules and utilities necessary for adding style and design to content, for instance, adding color to backgrounds and formatting content in one or multiple columns for easier reading.
What can JS really do?
Where JS really excels though, and one of the reasons it is used for so many development tasks, is its ability to execute prepared code in response to some action taken on a web page. One of the most common types of events is a ‘click’ event, i.e. when a user has clicked on a button or some other item on a web page. Detecting this click, JS would then run a prepared body of code that accomplishes a desired task.
APIs themselves are canned programs that allow you to accomplish some complex tasks that might otherwise not be achievable. Programs like these are developed to accomplish some predictable computing tasks, and they can be called whenever needed to perform their function and then go back into a rest state.
These programs fall into two general categories, those being browser APIs and third-party APIs. Browser APIs are built into your computer’s browser, and they are helpful for exposing certain elements of the computer environment itself, or for performing some complex tasks associated with it. Third-party APIs are not included in the browser, and so must be obtained from somewhere else in your environment.
Some of the more common uses of JS on the client side include playing browser video games, the generation of pop-up ads, redirecting a user to another page, sending data about user behavior to a server, loading new web page content without re-loading the page itself, controlling the display of streaming media, and fading objects in and out or re-sizing them.
Since the usage of JS is so widespread, it has become a frequent target for hackers and the criminal-minded element among computer users. However, a couple of fundamental restrictions prevent most attempts at hacking or corruption. The first restriction limits users to running web-related functions, rather than general purpose tasks like creating or deleting files.