如何在Javascript中从外部范围调用函数？

Question

Consider the code:

function foo()
{
    console.log('foo');
}

function bar()
{
    var foo = 5;
    foo(); // (*)
}

How to make (*) refer to outer function instead of local variable?

Answer 1

If the outer scope is the global scope, you can do

window.foo(); // assuming you're in a browser

If not, then you're out of luck. Give the local variable another name.

An example of when you're out of luck:

window.onload = function() {
    function foo()
    {
        console.log('foo');
    }

    function bar()
    {
        var foo = 5;
        foo(); // (*)
    }
}

The scope of the anonymous "load" handler function has no name, or any other handle by which the code in function "bar" could indicate that it wanted a reference to that "foo" instead of the local one.

Note that Coffeescript explicitly disallows this; it won't allow a local symbol to hide a more global one. (That's a controversial feature of the language , before you jump on the Coffeescript train.)

Answer 2

If your function is global you can use:

window.foo()

More info: http://www.w3schools.com/js/js_function_invocation.asp