What language is the underlying language of JavaScript implemented?

With the widespread application of JavaScript in Web applications, more and more people are interested in the underlying language it implements. In fact, the underlying JavaScript is implemented by C and C languages. This article will be based on the JavaScript language, explore how the underlying language is implemented, and introduce how the underlying language interacts with JavaScript.

1. C is the core of the underlying language of JavaScript

JavaScript is an interpreted language, but its performance is equivalent to that of a compiled language. This is due to the design and implementation of JavaScript's underlying language C. C is an object-oriented programming language that provides efficient memory management, an optimizing compiler, and a rich standard library. As a system-level language, C can directly operate computer hardware and call APIs provided by the operating system. It can handle large amounts of data and complex computing tasks, and can provide efficient algorithms and data structures.

The bottom layer of JavaScript is implemented by C language, and C is the basis for implementing the JavaScript engine of web browsers. The web browser parses the JavaScript code into bytecode through the JavaScript engine and generates an abstract syntax tree. The JavaScript engine then converts the bytecode into machine instructions and executes them. The key to JavaScript engine performance lies in optimizing the compiler in order to recognize and exploit the application's patterns and generate efficient machine code.

2. The role of C language in the bottom layer of JavaScript

C language is the second bottom language of JavaScript. The CJS bridging library allows C code to be used directly in JavaScript, which greatly expands JavaScript. operability. In JavaScript, low-level hardware objects such as sockets can be directly accessed through the C language, and the C language also provides efficient memory management and algorithm optimization, which can more effectively handle large-scale data, transmit and process pure binary data, thereby improving JavaScript Program performance.

When using C language to implement the bottom layer of JavaScript, you can use the functions and data structures provided by the standard library of C language. For example, you can use the malloc() function in the stdlib.h header file to dynamically allocate memory, and use the free() function to release memory. This can manage the memory of JavaScript applications more effectively and improve the performance of JavaScript programs.

In addition, C language and JavaScript can call each other. In JavaScript, by importing a C function into the JavaScript environment, you can call the C function from JavaScript and call the JavaScript function from C code. This interop makes integrating JavaScript with native code easier and more efficient.

3. The JavaScript underlying language interacts with the Web browser

In the Web browser, the JavaScript underlying language interacts with the Web API. Web API is a set of APIs provided by web browsers that can be accessed through JavaScript code. For example, APIs can be used to access the DOM structure, page elements can be obtained through JavaScript code, and the content of the web page can be dynamically updated.

JavaScript plays two roles: a client-side scripting language and a browser hosting language. Since JavaScript is a dynamic, interpreted language, it requires a JavaScript engine to evaluate and execute JavaScript code. At the same time, JavaScript also needs to interact with the web browser's API to update page content and respond to user interactions.

The JavaScript engine of modern web browsers uses many optimization techniques, such as JIT compilers and optimization algorithms. With the help of these technologies, JavaScript has become one of the most important languages ​​in web application development.

4. Summary

By understanding that the bottom layer of JavaScript is implemented by C and C languages, you can better understand the operation of JavaScript in Web applications. The underlying language provides JavaScript with the advantages of efficient memory management, an optimizing compiler, and a rich standard library. At the same time, the C language bridging library in JavaScript allows C functions to be called directly in JavaScript. This interoperability greatly improves the operability and performance of JavaScript programs. Therefore, understanding the underlying implementation of JavaScript and the basic knowledge of the underlying language is very important for developing efficient and stable JavaScript applications.

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