¿Cómo cambiar el color del borde de entrada de texto?

//set your input textfield to have a border
myInputBox.border = true;
//set default border color (in this case grey)
myInputBox.borderColor = 0x999999;
//when textfield is focused
myInputBox.onSetFocus = function() {
    //change the border color to red
    this.borderColor = 0xFF0000;
};
//when focus is taken off of text field
myInputBox.onKillFocus = function() {
    //reset the border back to original grey color
    this.borderColor = 0x999999;
};