What Is Javascript?

With its support for HTML and cascading style sheets, javascript helps make websites more dynamic and interactive. Used by tech giants like Google, Facebook, and Twitter, it’s one of the most widely-used programming languages in the world.

As a client-side language, javascript runs in a web browser rather than on a server. Web pages are interpreted by the user’s computer, which has to download, parse, and execute each script in order for it to function properly. The scripts can be used to automate tasks, add animations, and customize page footers. They can also be used to create chatbots, build project management tools, and develop real-time communication apps such as Zoom, Slack, and Google Meet.

A number of features make javascript unique, and the most important is its arithmetic operators. Unlike other languages, such as C, which require you to pre-compile code into machine code, javascript performs its compilation at runtime. This is called just-in-time compilation and makes the language very fast for simple functions and processes.

Among the other distinctive features of javascript are its scope chain and closures. Like most object-oriented languages, javascript uses scope chains to determine which variables and functions a given code snippet will see. Moreover, it supports nested functions, which are defined inside another function, and allows them to access the scope chain of their outer function for purposes such as referencing global objects or passing arguments. The scope chain is also what allows a nested function to call itself recursively.

The language also supports numeric data types, including the standard int, float, and bigint. It also includes numeric operator shortcuts, which shorten the length of numeric operations by allowing you to use parentheses or parenthese-less brackets when performing arithmetic operations. The built-in numeric types can be extended by defining custom data types.

As with other interpreted languages, javascript has a number of features designed to improve efficiency and ease of programming. Strings are represented as sequences of Unicode characters, which helps with internationalization, and operators such as toString and valueOf cast values from strings to numbers and vice versa. The eval function can even execute statements provided as strings at runtime.

Lastly, javascript has some optimization techniques to improve performance. These include inlining, which replaces a function’s code with its actual return value at the point of its invocation. For example, inlining replaces the return a + b with the actual code of the original function.

While javascript can be a bit complicated, it has become very popular and is used by the largest technology companies in the world. Every modern web browser has a javascript interpreter, and important tools, such as a debugger, are available for it. Static program analysis tools, such as ESLint and JSLint, scan javascript for compliance with a set of rules and standards. Additionally, many text editors have syntax highlighting support for the language. These tools, combined with a strong arithmetic, logic, and operator library, allow developers to quickly create a variety of useful applications.