Flash AS CreateTextField() issue

I'm creating a text field dynmaically and it works great however when I test the movie I can't seem to change any text (like a typical input box on a webpage for example), it appears to be only readonly. Can someone help me out?

this.createTextField("dynamic_txt", 1, 115, 9, 138, 22);
dynamic_txt.multiline = false;
dynamic_txt.wordWrap = false;
var my_fmt:TextFormat = new TextFormat();
my_fmt.font = "Arial";
my_fmt.size = 12;
my_fmt.color = 0x000000;
my_fmt.underline = false;
dynamic_txt.text = "This is my first test field object text.";
dynamic_txt.setTextFormat(my_fmt)开发者_Go百科;

dynamic_txt.type = "input";

add This line in your code.