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JS data types and variables refer to what, I believe that many inexperienced people do not know what to do, so this paper summarizes the causes of the problem and solutions, through this article I hope you can solve this problem.

Data types and variables of JS

JavaScript has six data types. The main types are number, string, object, and Boolean, while the other two types are null and undefined.

String string type: strings are described in single or double quotation marks. (use single quotation marks to enter a string containing quotation marks. For example, "The cow jumped over the moon."

Numeric data types: JavaScript supports integers and floating-point numbers. Integers can be positive, 0, or negative; floating-point numbers can contain a decimal point, an "e" (upper and lower case, which means "the power of 10" in scientific notation), or both.

Boolean type: possible Boolean values are true and false. These are two special values and cannot be used as 1 and 0.

Undefined data type: a value of undefined refers to the value that was held after the variable was created but before the variable was assigned a value.

Null data type: the null value just doesn't have any value and means nothing.

Object types: in addition to the various common types mentioned above, objects are also an important part of JavaScript, which will be described in more detail in later chapters.

In JavaScript, variables are used to store values in scripts, so that they can be represented by variables where they are needed. A variable can be a number, text, or something else.

JavaScript is a language that is not strict with data type variables, so it is not necessary to declare the type of every variable. Although variable declaration is not necessary, it is a good habit to declare variables before using them. You can use the var statement to declare variables. For example, the value stored in var men = true; / / men is of type Boolean.

Variable naming: JavaScript is a case-sensitive language, so naming a variable computer is different from naming it Computer.

In addition, the length of the variable name is arbitrary, but the following rules must be followed:

1. The first character must be a letter (uppercase and lowercase), or an underscore (_) or a dollar sign ($).

two。 Subsequent characters can be letters, numbers, underscores, or dollar signs.

3. Variable name cannot be a reserved word.

After reading the above, have you mastered what the data types and variables of JS refer to? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel, thank you for reading!

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