当方法具有相同名称的参数时访问闭包变量

Question

Consider the following code:

function() {
  var a = "Hello World";

  function foo(a) {
    alert(a);
  }
}

This will print the value passed to foo .

How can I access the a variable defined in the closure so that "Hello World" will be printed?

Answer 1

You can't because it gets overridden in the functions scope. I also don't understand why such a construct would be useful. It's very confusing to say the least. Just change the argument or variable name.

Answer 2

If you don't use var when declaring a variable, it will be global and you can access it via window.a . This also work if the outer function is bound to the window object.

By the way, if you have control over variable and parameter names, you better name them in a better and less confusing way