[RESOLVED] How to delete the last letter of the word acs2

[kofa]

hello
How to delete the last letter in acs2

var myListener:Object=new Object();
myListener.onKeyUp=functions(){
if (Key.getCode() == 65) {   // a
t.text =t.text+"a";}
if (Key.getCode() == 66) {  // b
t.text =t.text+"b";}
if (Key.getCode() == 8) {  // backspace
// i need code to delete the last letter 
}}
Key.addListener(myListener);
}