Reserved words that are not javascript

JavaScript is an advanced dynamic programming language that is widely used in various fields such as web development, client-side scripting, and server-side scripting. In JavaScript, reserved words refer to a set of keywords reserved by the programming language to support the semantics and syntax of the language.

However, in JavaScript, not all keywords are considered reserved words. In fact, only a small number of keywords in JavaScript are considered reserved words. The following are some keywords that are not reserved words in JavaScript:

1. let and const

let and const are new keywords introduced in ES6 for declaring blocks Level-scope variables and constants. Although let and const are very important concepts in modern JavaScript, they were not reserved words in earlier versions of JavaScript.

2. alert, confirm and prompt

alert, confirm and prompt are commonly used interactive windows in JavaScript. They are used to display messages to users, accept user input and ask questions. Whether the user confirms certain actions. Although these keywords are very common in JavaScript, they are not reserved words.

3. arguments and NaN

arguments is a special object used to represent the set of parameters received by the called function. NaN is the abbreviation of "Not-A-Number". Although they are common and important values, they are not reserved words in JavaScript.

4. undefined

As a special value in JavaScript, undefined represents an undefined variable or property. Although it is one of the most common values ​​in JavaScript, it is not a reserved word.

5. window and document

window and document are two important objects in JavaScript, which represent the window and document in the browser respectively. Using these objects, developers can perform various manipulations and interactions on the page. However, although they are frequently used keywords in JavaScript programming, they are not reserved words in JavaScript.

Generally speaking, in JavaScript, reserved words are a set of keywords reserved by the programming language to support the semantics and syntax of the language. Although most common JavaScript keywords are considered reserved words, there are still some important keywords that are excluded. Understanding JavaScript's reserved words and exceptions is very important to writing high-quality code.

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