Call variables from one javascript file to another

Question

How can I call the variables that I stored in one javascript file from another?

var.js

var VAR = new Object;
VAR.myvalue = "Yeah!";

then I want to use VAR.myvalue here

sample.js

alert(VAR.myvalue);

Answer 1

First, instead of

var VAR = new Object;
VAR.myvalue = "Yeah!";

Opt for

var VAR = {
    myvalue: "Yeah!"
 };

But so long as var.js is referenced first, before sample.js, what you have should work fine.

var.js will declare, and initialize VAR, which will be read from the script declared in sample.js

Answer 2

Include both JavaScript file in one HTML file, place sample.js after var.js so that VAR.myvalue is valid:

<script type="text/javascript" src="var.js"></script>
<script type="text/javascript" src="sample.js"></script>

Answer 3

Try separating your scope using a module pattern. This will eliminate headaches in the future.

var.js

var someVar = (function () {
  var total = 10; // Local scope, protected from global namespace

  return {
    add: function(num){
      total += num;
    }
  , sub: function(num){
      total -= num;
    }
  , total: function(){
      return total;
    }
  };
}());

Then you can use that object's methods and properties from anywhere else.

sample.js

someVar.add(5);
someVar.sub(6);
alert(someVar.total());