Trying to use code found in working PDF from online in LC. (Keystroke Event)

I found a PDF online (at http://www.planetpdf.com/developer/article.asp?ContentID=javascript_dy namic_updates_w) that works on my iPad running PDF Expert for iPad 5.0.4.

I tried to recreate it in LiveCycle ES4 using the same code. However, the author says to place the code in the "keystroke" event. I can't find a "keystroke" event. I've tried it and variations in change, preOpen, and exit without any success.

Can someone help me?

This is the exact functionality I need and the only example that I have seen work in both a PC environment and an iPad (running PDF Expert).

Thanks!

Dan

The code can be found at: http://www.planetpdf.com/developer/article.asp?ContentID=javascript_dy namic_updates_w

The sample PDF can be found at: http://www.planetpdf.com/codecuts/pdfs/Populate.pdf

I am specifically looking at the code in the dropdown box called "Three" - which is captioned as "Dynamic"

Code follows:

==========

/* This version updates a secondary combobox based on the entry

** selected by the user dynamically. The keystroke event should

** be processed until the value is about to be committed (as

** indicated by event.willCommit). */

if (!event.willCommit) {

    var f = this.getField("Four");

    f.clearItems();

    /* In a keystroke event, event.change contains the non-export value of the item selected by the user. */

    switch (event.change) {

        case "Cities":

          ;       f.setItems(["Paris", "Berlin", "Amsterdam", "Rome"]);

        break;

        case "Fruit":

          ;       f.setItems(["Bananas", "Mangos", "Strawberries", "Papayas"]);

        break;

        case "Garden Tools":

          ;       f.setItems(["Hoe", "Rake", "Leaf blower", "Shovel"]);

        break;

    }

}