Move cursor inside textarea to end

I have a text area control on a form that is supposed to accept 5 digit US zip codes. I have assigned the control a keyUp event that checks the number of characters entered until it reaches 5 then forces a new line.

public function forceNewLine(event:KeyboardEvent):void
{
    var maxLineChars:int = 5;
    var currentLine:int = 1;
    var numChars:int;

    numChars = (txtList.text.length);
    currentLine = Math.round(txtList.text.length / 6);

    if (numChars == (maxLineChars * currentLine))
    {
        txtList.text = txtList.text + "\n";
        txtList.setCursorPosition() 
        //This is not a function I have defined but I think I need too..
    }
}

<s:TextArea id="txtList" keyUp="forceNewLine(event)"/>

It works fine except that when开发者_运维百科 the new line is inserted, the cursor moves to the beginning of the textarea. I want it to go to the end.

Try using the selectRange function of the spark textArea.

txtList.selectRange(txtList.text.length, txtList.text.length)