Type More Than 1 Char Into A Drop Down List

I cannot remember the site nor the author, but it works BEAUTIFULLY!
I have changed the timeoutInterval to 500 milliseconds as I type with one finger - the original was 250 or even less.

<script language="JavaScript">
// script allows you to type more than one character into a drop-down list
//
//A typical drop-down need to have ONKEYPRESS and ONKEY functions added
//
//Example: <SELECT ID='vc_DESCRIPTION' NAME='vc_DESCRIPTION' onkeypress='listbox_onkeypress()' onblur='listbox_onblur()'>


var toFind = ""; // keyboard buffer
var timeoutID = ""; // process id for timer - when stopping the timeout
var timeoutInterval = 500; // milliseconds - keyboard buffer
var timeoutCtr = 0; // initialise of timer countdown
var timeoutCtrLimit = 3; // number of times timer is allowed to count down
var oControl = ""; // maintains a global reference to the user control

function listbox_onkeypress(){

window.clearInterval(timeoutID)
oControl = window.event.srcElement;
var keycode = window.event.keyCode;

if(keycode >= 32 ){
var c = String.fromCharCode(keycode);
c = c.toUpperCase();
toFind += c ;
find(); // search the listbox
timeoutID = window.setInterval("idle()", timeoutInterval); // restart the timer
}
}

function listbox_onblur(){ // function is called when user leaves listbox

window.clearInterval(timeoutID);
resetToFind();
}

function idle(){ // function is called if timeout expires - 3rd time stops timer and clear kb buffer

timeoutCtr += 1

if(timeoutCtr > timeoutCtrLimit){
resetToFind();
timeoutCtr = 0;
window.clearInterval(timeoutID);
}
}

function resetToFind(){

toFind = ""
}

function find(){

var allOptions = document.all.item(oControl.id);

for (i=0; i < allOptions.length; i++){
nextOptionText = allOptions(i).text.toUpperCase();

if(!isNaN(nextOptionText) && !isNaN(toFind) ){
nextOptionText *= 1;
toFind *= 1;
}

if(toFind == nextOptionText){
oControl.selectedIndex = i;
window.event.returnValue = false;
break;
}

if(i < allOptions.length-1){
lookAheadOptionText = allOptions(i+1).text.toUpperCase();

if( (toFind > nextOptionText) && (toFind < lookAheadOptionText) ){
oControl.selectedIndex = i+1;
window.event.cancelBubble = true;
window.event.returnValue = false;
break;
}
}
else{

if(toFind > nextOptionText){
oControl.selectedIndex = allOptions.length-1
window.event.cancelBubble = true;
window.event.returnValue = false;
break;
}
}
}
}
</script>