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What is the role of variables in javascript? in view of this question, this article introduces the corresponding analysis and solutions in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible way.

In javascript, a variable is a container that temporarily stores values and can be used to store data and set, update, or read the contents of the variable as needed. Using variables can give a short and easy-to-remember name for a piece of data to be used in the program, and you can also save the data entered by the user or the results of the operation.

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

Variables are one of the foundations of all programming languages and can be used to store data, such as strings, numbers, Boolean values, arrays, and so on, and to set, update, or read the contents of variables as needed.

The value of the variable can change at any time during the operation of the program, which can give a short and easy-to-remember name for a piece of data to be used in the program. in addition, it can also save the data entered by the user or the result of the operation.

Define variable

In JavaScript, you need to use the var keyword to define variables. The syntax format is as follows:

Var variable name

To give a few examples:

Var str; / / to store the string var age; / / to store the age var prePage; / / to store the previous page

When defining variables, you can define one or more variables at a time. If you define more than one variable, you need to separate the variable names with commas, as shown in the following example:

Var a, b, c; / / declare multiple variables at the same time

After the variable is defined, if the variable is not assigned a value, then the variable is assigned an initial value-undefined (undefined).

Naming rules for variables

In JavaScript, variable names cannot be defined casually, and you need to follow the naming rules for identifiers, as shown below:

Variable names can contain numbers, letters, underscores _, and the dollar sign $

Chinese characters cannot appear in variable names

Variable names cannot contain spaces

Variable name cannot be a keyword or reserved word in JavaScript

The variable name cannot start with a number, that is, the first character cannot be a number.

When defining a variable, the variable name should be as meaningful as possible so that it can be easily understood by yourself or others. For example, you can use name to define a variable to store the name, and dataArr to define an array type variable.

When the variable name contains multiple English words, it is recommended to use the hump naming method (big hump: the first letter of each word is capitalized, such as FileType, DataArr; hump: the first letter of the first word is capitalized after lowercase, such as fileType, dataArr).

Assign a value to a variable

After the variable is defined, you can assign a value to the variable using the equal sign =. The one to the left of the equal sign is the name of the variable, and the right side of the equal sign is the value to be assigned to the variable, as shown in the following example:

Var num; / / defines a variable numnum = 1; / / assigns the variable num to 1

Alternatively, you can assign values to variables while defining them, as shown in the following example:

Var num = 1; / / define a variable num and assign it to 1var a = 2, b = 3, c = 4; / / define three variables a, b, c at the same time and assign values as 2, 3, 4 var a = 2, / / to make the code look neater, the previous line of code can also be written like this / b = 3. The answer to the question about the role of variables in javascript is shared here. I hope the above content can be of some help to you. If you still have a lot of doubts to be solved, you can follow the industry information channel to learn more about it.

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