Constant - MDN Web Docs Glossary: Definitions of Web-related terms 编辑

A constant is a value that the programmer cannot change, for example numbers (1, 2, 42). With variables, on the other hand, the programmer can assign a new value to a variable name already in use.

Like variables, some constants are bound to identifiers. For example, the identifier pi could be bound to the value 3.14... .

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General knowledge

• Constant on Wikipedia