在javascript中使对象变为非全局对象

Question

I have a function in JavaScript which looks something like this:

foo=function(listenerObject)
{
  a={count:0};
  foo2=function(){
    //does stuff with a
  }
  //register listenerObject to callback the function foo2
}

The problem is I end up using this function to register multiple listeners, but they all end up sharing the same 'a' object. Is there a way to keep an object declaration inside a function from creeping into the global scope. In other words I would like to prevent being able to do something like this

fun=function(){o={count:0}}
o.count++//o is now in the global scope

Answer 1

Use var . Really, you should be declaring all of your variables with var otherwise you'll, as you found out, get a bunch of global variables stepping on each other.

Example:

var foo = function(listenerObject) {
  var a = { count: 0 };
  ...
};