What is the difference between these two function declarations in JavaScript?

Question

Possible duplicate:
JavaScript: var functionName = function () {} vs function functionName () {}

In JavaScript, we can say:

function a() {};

Or we could say

var a = function() {};

Can someone explain to me exactly how they differ, which, if any, are preferable and under what circumstances can each of them be used?

Any links or external readings will be highly appreciated.

+5

James wiseman Jan 31 '11 at 19:38

4 answers

First

function a() {};

FunctionDeclaration FunctionExpression. , FunctionDeclaration FunctionExpression, , .

# 1)

0,function a() {} //FunctionExpression

# 2)

(function a() {} ()); //FunctionExpression

№ 3)

var b = function a() {}; //FunctionExpression

# 4)

foo(function a(){}); //FunctionExpression

var a = function() {};

FunctionExpression .

1)

2)

:

+2

weirdFactory 14 . '11 18:04

one - , - , . - javascript-.

0

brian brinley 31 . '11 19:40

0

Mikhail Jan 31 '11 at 19:42

Jason lebrun · Accepted Answer · 2011-01-31T19:41:13+0000

One is a function declaration, and one is a function expression.