Hello world example for dependency injection

There is a lot of variability in what Google pulls up and none of it seems to distill the basics very well.

Can someone provide a "hello world" example of JavaScript dependency injection.

I've used DI in PHP but with out the simple class-object paradigm, I'm finding it difficult to get a grasp of how this would function in JavaScript.

A hello world example of the method angular.js uses would be best, and why it uses toString() if it is not too complex would help.

Thanks

I found this blog entry to be helpful when looking at DI with JavaScript: http://merrickchristensen.com/articles/javascript-dependency-injection.html

Below is a simple example of using angular.js for dependency injection: 

 function HelloWorld($scope){
     $scope.name="ajay";
  }

HelloWorld.$inject = ['$scope'];