Textinput, count letters

1

Hi.
Sorry for the title, I can’t come up with a good one for my problem.

I’m having problems with some code i’m working on.
I’ll try to explain as good as I can.

I have a textinput that updates a textfiled on change.
I also have a textfield that shows how many chars you have typed.

 
on(change)
{
     _root.test_txt.text = this.text;
     _root.chars_txt.text = this.text.length;
}

What I want is that when (for example) the letter A is typed it counts it two times.
KIRUPA becomes 7 letters.

I was thinking of having something like numTest++

 
on(change)
{
     myString = this.text;
     for(var i:Number = 0; i < myString.length; i++)
     {
          if(myString.charAt(i) == "A")
          {
               numTest++
          }
      }
     _root.chars_txt.text = this.text.length + numTest;
 
}

But I only want the thing to count the letter once. Now it adds numTest++ on the same letter when typing some more. ADDD becomes 8 chars. (Should be 5).

FLA can be downloaded here: http://www.lazeeonline.com/help.zip

Thnx in advance.