Closures _1 (concept)

Ah, closures, I only know a function of a function package (there are eggs with ah! Throw)

1. Start with a scope.

　　js not block-level scope, but there js function scope

　　js global variables and local variables

　　Define variables within the function of the external function is not accessible, which is a local variable.

　　Defined in advance in an external function variables can be accessed inside a function, this is a global variable.

2. If I wanted to get outside variables inside the function how to do it?

　　Then I came alive again in a function 1 function 2, function 1 is used to define the value of the function 2 exposed.

　　

　　

 

　　This is a closure.