Flash IsNumber

Make new Flash File
Add one Input Text box Instance Name is "txtNummer"
Add one Dynamic Text Instance Name is "LblErr"
Add one button Instance Name is "submit_btn"
Select Fist Frame1 and Past code

Code:
function IsNumber(numberText):Boolean {
if (int(numberText) == 0) {
LblErr.htmlText = "*Enter Number Only.";
return true;
}
LblErr.htmlText = "";
return true;
}

submit_btn.clickHandler = function() {
if (!IsNumber(txt)) { Selection.setFocus(txtNummer);
}
};