Display as Text field won't populate from select

Question

I'm an Oracle Forms person trying to learn APEX. Love it but having problems with seemingly simple stuff. I made a simple page exactly from sample code found from Oracle documentation and still can't get to work. Appreciate any help.
Have simple form with 2 fields. One field P400_DEPTNO which is select field. Code in the HTML Form Element Attributes: onchange="javascript:getDNAME(this);"
The other field is D400_DNAME which have as Display as Text(escape special characters, does not save state)
I have application item G_DEPTNO
application process GET_DNAME:
DECLARE
vDNAME VARCHAR2(100);
BEGIN
SELECT DNAME INTO vDNAME FROM DEPT WHERE DEPTNO = :G_DEPTNO;
htp.p(vDNAME);
EXCEPTION WHEN OTHERS THEN
htp.p('No such department!');
END;
code in HTML Header of page 400:
<script type="text/javascript">
function getDNAME(filter)
var get = new htmldb_Get(null,&APP_ID.,'APPLICATION_PROCESS=GET_DNAME',0);
get.add('G_DEPTNO', filter.value);
var ret = get.get();
if(ret)
var d = document.getElementById("P400_DNAME");
d.innerHTML = ret;
get = null;
</script>
I'm getting this error when running page:
get error:
Line: 25
Char: 3
Error: 'null' is null or not an object
when I view source: line 25 is:
d.innerHTML = ret;
I have tried so many variations. Could something on my system not be installed correctly or am I just missing something simple? Appreciate any help offered.
Gayle

Answer 1

Hi Vinad:
I am running version 3.0.0.00.20.
I followed the directions step by step from http://apex.oracle.com/pls/otn/f?p=56976:1:2691826935187310
I assume the code you are interested in is the javascript code:
HTML HEADER
<script type="text/javascript">
function getDNAME(filter)
var get = new htmldb_Get(null,$v('pFlowId'), 'APPLICATION_PROCESS=GET_DNAME',0);
get.add('G_DEPTNO', filter.value);
var ret = get.get();
if(ret)
var d = document.getElementById('P1_DNAME');
d.innerHTML = ret;
get = null;
</script>
On Demand Application Process
DECLARE
vDNAME VARCHAR2(200);
BEGIN
SELECT WHS_LST_NM INTO vDNAME FROM dw_tst.emp_dim@dm_dev
WHERE emp_id = :G_DEPTNO;
htp.p(vDNAME);
EXCEPTION WHEN OTHERS THEN
htp.p('No such employee!');
END;
Please let me know if you need any other information. Thank you.