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In this article, the editor introduces in detail "is javascript dynamic?", the content is detailed, the steps are clear, and the details are handled properly. I hope this "javascript is dynamic" article can help you solve your doubts.

Javascript is dynamic, a dynamically typed, weakly typed, prototype-based language. In JavaScript, when assigning a value to a variable, it does not need to consider its type; and it can dynamically modify the properties of the object, there is no way to know the type of variable at compile time, it can only be determined at run time.

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.

What are static and dynamic languages?

Static language (strongly typed language)

Static languages are languages that can be determined by the data type of a variable at compile time, and most statically typed languages require that the data type be declared before using the variable.

Dynamic language (weakly typed language)

A dynamic language is a language that determines data types at run time. A variable does not need a type declaration before it is used, and usually the type of the variable is the type of the value to which it is assigned.

Is javascript a dynamic language?

Javascript is a dynamic language. JavaScript can dynamically modify the properties of objects, there is no way to know the type of variables at compile time, it can only be determined at run time.

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.

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.

Advantages and disadvantages of static and dynamic languages

Advantages of statically typed languages:

1. Errors with mismatched types can be found at compile time, and the editor can help us avoid some errors that may occur during the run of the program in advance.

2. 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.

Disadvantages of statically typed languages:

1. Forcing programmers to write programs according to strong contracts and specifying data types for each variable, in the final analysis, 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.

2. Type declarations also add more code, and these details distract programmers from thinking about business logic during programming.

Advantages of dynamically typed languages:

Less code is written and looks more concise, so 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.

Disadvantages of dynamically typed languages:

The type of the variable cannot be guaranteed, so type-related errors may occur during the run time of the program. It's like buying a bag of spicy beef gluten in the store, but you don't know if it tastes like beef until you really eat it.

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