Using get_AJAX_SELECT_XML causes form to "hang" in IE but notin FIREFOX

Question

I have 2 fields on a form that are coordinated to make use of the javascript call of get_AJAX_SELECT_XML,
P118_CLONE_DEPT
P118_CLONE_POS
The HTML form element attributes for P118_CLONE_DEPT are:
onchange="get_AJAX_SELECT_XML(this,'P118_CLONE_POS')"
The LOV is supposed to be automatically populated for P118_CLONE_POS once you select a department for P118_CLONE_DEPT.
The code hangs in IE at the same place, but never hangs in Firefox. If you let the browser sit, control seems to eventually come back, but it may take 5 to 6 minutes - most users would bail out well before 5 minutes have elapsed. I have no clue what is causing this.
This is triggered by picking a deparment that has 9 positions, then a deparment that has 0 positions and then repeating it all over again. ie.
dept 854 with 9 positions
dept 857 with 0 positions
dept 854 with 9 positions
dept 857 with 0 positions
Here is the function with alerts:
function get_AJAX_SELECT_XML(pThis,pSelect){
     var l_Return = null;
     var l_Select = html_GetElement(pSelect);
alert('1in get_AJAX_SELECT_XML value of item is ('+ pThis.value + ')' );
     var get = new
htmldb_Get(null,html_GetElement('pFlowId').value,'APPLICATION_PROCESS=clone_Select_XML',0);
alert('2in get_AJAX_SELECT_XML value of item is ('+ pThis.value + ')' );
     get.add('TEMP_POS_TYPE_CD_DEPT',pThis.value);
alert('3in get_AJAX_SELECT_XML value of item is ('+ pThis.value + ')' );
//alert('2 in get_AJAX_SELECT_XML value of item is ('+ pThis.value + ')' );
     gReturn = get.get('XML');
alert('4in get_AJAX_SELECT_XML value of item is ('+ pThis.value + ')' );
     if(gReturn && l_Select){
          var l_Count = gReturn.getElementsByTagName("option").length;
alert('5in get_AJAX_SELECT_XML l_Count is' + l_Count );
          l_Select.length = 0;
alert('6in get_AJAX_SELECT_XML l_Count is' + l_Count );
          for(var i=0;i<l_Count;i++){
alert('7in get_AJAX_SELECT_XML i is' + i );
               var l_Opt_Xml = gReturn.getElementsByTagName("option");
alert('8in get_AJAX_SELECT_XML about to call appendToSelect');
               appendToSelect(l_Select, l_Opt_Xml.getAttribute('value'), l_Opt_Xml.firstChild.nodeValue)
alert('8in get_AJAX_SELECT_XML i is' + i );
alert('9in get_AJAX_SELECT_XML i is' + i );
     get = null;
alert('10in get_AJAX_SELECT_XML i is' + i );
It hangs just after alert # 3 is displayed on the screen. Does this mean the call "     gReturn = get.get('XML');" is taking a while to process? Is it my browser? Once control is returned, the position LOV is filled in correctly.

Answer 1

To put an example here would not allow you to debug the problem because I can't replicate the table that the query goes against. The table I use has 160 different departments that have 1 or more positions.
Instead I have altered your code and page 37 and got the "hanging" to occur. I have altered the process "get_AJAX_SELECT_XML" to be,
declare
l_cnt number;
l_o_name varchar2(2000);
begin
owa_util.mime_header('text/xml', FALSE );
htp.p('Cache-Control: no-cache');
htp.p('Pragma: no-cache');
owa_util.http_header_close;
l_cnt := 0;
htp.prn('<select>');
for rec in (
select distinct position
from position
where position_type_cd = substr(:TEMP_POS_TYPE_CD_DEPT,7,1) and
department_cd = substr(:TEMP_POS_TYPE_CD_DEPT,1,6) and
position_status_cd = 'A'
loop
l_cnt := l_cnt + 1;
htp.prn('<option value="' || rec.position || '">' || rec.position || '</option>');
end loop;
if l_cnt = 0 then
htp.prn('<option value="' || '-'|| '">' || '-' || '</option>');
end if;
htp.prn('</select>');
end;
From above, I have added some code to detect when no positions are found, but including it or not still yields the same "hang" results. The field "TEMP_POS_TYPE_CD_DEPT" is a string with department and department-type concatenated ie. 0021XXP
On page 37, I have left it alone. The item P37_ITEM_SELECT is fired on the "Element region" through the element attributes of
onchange="get_AJAX_SELECT_XML(this,'P37_SELECT_DROP_XML').
Its "List of values definition" is:
select department_cd || ' - ' || department "disp", department_cd || 'P' "rval"
from department order by 2
To get the "hanging" on page 37 is a little tricker. I go to a department with positions in the LOV for P37_ITEM_SELECT that is near the end of the list and select it. I then go off to other screens that I have open (ie, go to note-pad and type some text, go to MS outlook and check mail). When I come back to the screen with page 37 and just hit the "up-arrow" key to go to a department with positions, that is when the hanging occurs. ie
1. go to dept 0854 (has 9 positions)
2. go to dept 0857 (has 0 positions) via a "down-arrow" key
3. switch tasks for about a minute ie. notepad, outlook. This is the tricky part,
as step 4 may or may not work, but after 3 tests in a row I have got it to work.
4. go to dept 0854 via the "up-arrow" and get "hanging" behaviour
In the LOV for P37_ITEM_SELECT, the last 4 depts shown are:
0854, 9 positions
0857, 0 positions
0862, 2 positions
0873, 0 positions
Does this help?