Functions allow you group together some code, give this code a name, and reuse it later, addressing it by name. Let's see an example:
function sum(a, b) { var c = a + b; return c; }
What are the parts that make up a function?
The
function
statement.The name of the function, in this case
sum
.Expected parameters (arguments), in this case
a
andb
. A function can accept zero or more arguments, separated by commas.A code block, also called the body of the function.
The
return
statement. A function always returns a value. If it doesn't return value explicitly, it implicitly returns the valueundefined
.
Note that a function can only return a single value. If you need to return more values, then simply return an array that contains all of the values as elements of this array.