Function Object (JavaScript)

functionName

Required. The name of the newly created function

argname1...argnameN

Optional. A list of arguments the function accepts.

body

Optional. A string that contains the block of JavaScript code to be executed when the function is called.

The function is a basic data type in JavaScript. Syntax 1 creates a function value that JavaScript converts into a Function object when necessary. JavaScript converts Function objects created by Syntax 2 into function values at the time the function is called.

Syntax 1 is the standard way to create new functions in JavaScript. Syntax 2 is an alternative form used to create function objects explicitly.

For example, to declare a function that adds the two arguments passed to it, you can do it in one of two ways:

var add = function(x, y) {
     return(x+y);
}

In either case, you call the function with a line of code similar to the following:

add(2, 3);

Note
When you call a function, make sure that you always include the parentheses and any required arguments. Calling a function without parentheses causes the function itself to be returned, instead of the return value of the function.

0...n Properties |arguments Property | callee Property | caller Property | constructor Property | length Property (Function) | prototype Property

apply Method | bind Method | call Method | toString Method | valueOf Method

Supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards, Internet Explorer 10 standards. Also supported in Windows Store apps. See Version Information.

Reference