如何将匿名函数内的变量导出到JavaScript中的全局作用域？

Question

I have this code

((function(){
var a=2;
var b=3;
var c=b+a;
alert(c);//alert 5
})());
alert(c); //no alert

My question is which ways I can exports c to the global scope? If you can give all the ways. Thank you!

Answer 1

var c = ((function(){
    var a=2;
    var b=3;
    var c=b+a;
    alert(c);//alert 5
    return c;
})());
alert(c);

There are any number of ways to do this. You could implicitly or explicitly do property assignment on the global as well:

window.c = b+a;
this.c = b+a;
c = b+a;

Answer 2

It's very simple! All global variables in JavaScript are actually a child attribute of the "window" object, so declaring a variable in global scope adds makes that variable an attribute of the window object. From your anonymous function, you can place 'c', or other variables into a global scope simply by doing the following...

window.c=b+a;
alert(c); // Same!

Enjoy :)

Answer 3

var c=0;
((function(){
    var a=2;
    var b=3;
    c=b+a;
    alert(c);//alert 5
})());

alert(c); //no alert

Answer 4

 (function (window) { // this is local var c = 'local'; // export to the global scope window.c = c || ''; })(window); // Pass in a reference to the global window object console.log(c) // => 'local' 

You can also pass in few other objects and that is not only limited to just one. Here is a really good explanation of how it works