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This article mainly introduces whether javascript is a dynamic language, the article is very detailed, has a certain reference value, interested friends must read it!

Javascript is a dynamic language. It is a dynamically typed, weakly typed, prototype-based language. In JavaScript, when assigning a value to a variable, you don't need to consider its type, so it is a typical dynamically typed language.

The operating environment of this tutorial: windows7 system, javascript1.8.5 version, Dell G3 computer.

Programming languages can be divided into two categories according to data types, one is statically typed language, the other is dynamically typed language.

A statically typed language determines the type of a variable at compile time, while a dynamically typed language does not have a type until the variable is assigned a value when the program is running.

Javascript is a dynamic language. In JavaScript, when assigning a value to a variable, you don't need to consider its type, so JavaScript is a typical dynamically typed language.

JavaScript is a dynamically typed, weakly typed, prototype-based language.

The difference between statically typed language and dynamically typed language

First of all, the advantage of statically typed language is that it can find type mismatch errors at compile time, and the editor can help us avoid some errors that may occur during the program run in advance. Secondly, if the data type is clearly defined in the program, the compiler can also optimize the program according to this information to improve the execution speed of the program.

The disadvantage of statically typed language is that first of all, it forces programmers to write programs according to strong contracts and specify data types for each variable. In the final analysis, it is only a means to assist us in writing programs with high reliability, not the purpose of writing programs. After all, most people write programs to complete the delivery of production requirements. Second, type declarations add more code, and these details distract programmers from thinking about business logic during programming.

The advantage of dynamically typed languages is that less code is written and looks more concise, and programmers can focus more on business logic. Although not distinguishing types can make a program difficult to understand in some cases, on the whole, the less code and the more focused on logical expression, the more helpful it is to read the program.

The disadvantage of dynamically typed languages is that they cannot guarantee the type of variables, so type-related errors may occur during the run time of the program.

The tolerance of variable types in dynamically typed languages brings great flexibility to actual coding. Since there is no need for type checking, we can try to call any method of any object, regardless of whether it was originally designed to own the method.

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