Changing lowercase to Uppercase HELP!

Hi All,

I need to ensure that the output from my text box is uppercase at all times.

The text fields are

friendsName_tf
messageOne_tf
messageTwo_tf

My code is thus so far:

private function displayForm() {
//Setup intereaction on each of the form elements
this.error_tf.visible = false;
this.error1_tf.visible = false;
new FormElement(this.yourName_tf, this.yourName_tf.text, 100, 1);
new FormElement(this.yourEmail_tf, this.yourEmail_tf.text, 100, 2);
new FormElement(this.friendsName_tf, this.friendsName_tf.text, 100, 3);
new FormElement(this.friendsEmail_tf, this.friendsEmail_tf.text, 100, 4);
new FormElement(this.messageOne_tf, this.messageOne_tf.text, 10, 5);
new FormElement(this.messageTwo_tf, this.messageTwo_tf.text, 20, 6);
new FormElement(this.email1_tf, this.email1_tf.text, 100, 7);
new FormElement(this.email2_tf, this.email2_tf.text, 100, 8);
new FormElement(this.email3_tf, this.email3_tf.text, 100, 9);
this.help01.addEventListener(MouseEvent.CLICK, goWindow01);
this.help02.addEventListener(MouseEvent.CLICK, goWindow02);
}

    private function checkCaps(p_event:Event) {
        var str:String = "friendsName_tf"
            trace(str.toLowerCase()); // example.
            trace(str.toUpperCase()); // EXAMPLE.
            str = str.toUpperCase();
    }

Am i calling the name of the text field properly? do i need to call the function? if so where?

I am very much still learning AS3 so please help…:hr:

Cheers