JS: Define Function

Create a Function

There are 3 ways to create a function.

1. By the keyword function.
2. By Arrow Function expression. Most simple. 〔see JS: Arrow Function〕
3. By constructor with keyword Function. 〔see JS: Function Constructor〕

Keyword “function”

The syntax is:

function name (parameters) {body_statements}

Return Statement

In the function body, you can have 0 or more return expr.

When program reaches the return statement, it'll exit the function, and return the value.

Function without return statement returns the value undefined.

for detail, see JS: Function Parameters and other pages.