Check whether characters in input textfield are numbers or letters?

[garion1]

I just can't get this right.
I have two textfields:

1. inputTxt (INPUT)
2. statusTxt (DYNAMIC)

I have a button, which when pressed should check whether the characters entered into the input field are numbers or letters.
I have tried:

private function onMouseUp(evt:MouseEvent):void {
   if (isNaN(inputTxt.text)) {
      statusTxt.text = 'You have not entered a number';
   }else {
      statusTxt.text = 'You have entered a number';
   }
}

I realise now that isNAN() only checks a variable value rather than a string value.
How does one do this?

[Diniden]

just put your conditional like this if(isNan(Number(inputTxt.text))) and that should fix it right up.

[garion1]

Thanks Diniden
I had a feeling I needed to declare the data type somewhere.
Works perfectly.

[Diniden]

You aren't really declaring the data type there. Number(object) is a just a function to try and convert the parameter (you can almost say it's casting the object to number...but not really as far as how flash processes things) to a number of some sort. if it fails it returns NaN.