如何在javascript中引用函数对象的成员？

Question

I'm trying to do something like this:

function foo() { alert(this.bar); }
foo.bar = "Hello world";
foo();

That doesn't work because I believe this refers to the global object ( window ) rather than foo . How do I make it work?

Answer 1

this refer to the object used to call the method. By default, it will be the window object.

In your case, you should get the parameter in the function object directly using the named function as it is available in the scope.

function foo() { alert(foo.bar); }
foo.bar = "Hello world";
foo();

You shouldn't use this as doing something like this:

foo.call({})

this will be equal to the empty object.

Answer 2

Possibly try using prototype :

 function foo() { alert(this.bar); } foo.prototype.bar = "Hello world"; new foo(); //new object 

Recommended option:

 function foo(bar) { //constructor argument this.bar = bar; } foo.prototype.getBar = function() { alert(this.bar); }; new foo("Hello world").getBar(); 

Answer 3

I'd choose to do it this way, as it makes use of the prototype chain.

function Foo() { return (this===window) ? new Foo() : this; }
Foo.prototype.hi = function() { alert(this.bar) };
Foo.prototype.bar = "Hi!";

var tmp = new Foo();
tmp.hi();