Was this page helpful?
Your feedback about this content is important. Let us know what you think.
Additional feedback?
1500 characters remaining
Export (0) Print
Expand All

Function Object (JavaScript)

Creates a new function.

function functionName([argname1  [, ...[, argnameN]]])
functionName = new Function( [argname1,  [... argnameN,]] body );


Required. The name of the newly created function


Optional. A list of arguments the function accepts.


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:

function add(x, y)
   return(x + y);

var add = function(x, y) {

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

add(2, 3);

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.

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, Internet Explorer 11 standards. Also supported Store apps (Windows 8 and Windows Phone 8.1). See Version Information.

© 2015 Microsoft