Function

Summary

Creates a new function.

Syntax

function functionName ( [ argname1  [, ...[, argnameN ] ] ] )

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

functionName: Required. The name of the newly created function
argname1…argnameN: Optional. A list of arguments the function accepts.
parameters: Optional. Parameters are the named arguments in the function declaration’s arguments list. Parameters must be valid identifiers. If there is more than one, parameters are separated by commas.
body: Optional. A string that contains the block of JavaScript code to be executed when the function is called.

Examples

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

//Method 1
 function add(x, y)
 {
    return(x + y);
 }

//Method 2
 var add = function(x, y) {
      return(x+y);
 }

//In either case, you call the function with a line of code similar to this:
 add(2, 3);

Remarks

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.

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.

Properties

prototype Property

Methods

valueOf Method

Microsoft Developer Network: Article