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

A parameter is a named variable passed into a function. Parameter variables are used to import arguments into functions.

Note the difference between parameters and arguments:

• Function parameters are the names listed in the function's definition.
• Function arguments are the real values passed to the function.
• Parameters are initialized to the values of the arguments supplied.

Two kinds of parameters:

input parameters

the most common kind; they pass values into functions. Depending on programming language, input parameters can be passed several ways (e.g., call-by-value, call-by-address, call-by-reference).

output/return parameters

primarily return multiple values from a function, but not recommended since they cause confusion

Learn more

General knowledge

• Difference between parameter and argument on Wikipedia

Technical reference

• Function declaration
• Function expression