Setting the value of an Application Item (setting a global variable);

Question

In APEX 3.2.0.00.27, I need to initialize a global variable to 0 to implement a variable for testing to see if anything on the page has changed. Will update to 1 when certain select lists on the page are changed. Have read through some similar questions and replies within the forum as well as other blogs and sites. So, I believe what I am doing is the way to go about this. Unfortunately, my initialization of an application item/global isn't happening yet. here's a rundown of what has been implemented:
1) created an application item, G_CLASSIFICATION_ID_NEW in the shared components;
2) created Javascript (JS) function called by addLoadEvent in the page html header region so when the page loads, the G_CLASSIFICATION_ID_NEW global/application item should get set to 0 with the following JS and using AJAX and htmldb_GET:
<script type="text/javascript">
function initVars()
alert("before get initvars");
var get = new htmldb_Get(null,$x('pFlowId').value,null,22);
get.add('G_CLASSIFICATION_ID_NEW', 0);
gReturn = get.get();
if(gReturn){
alert(gReturn.value);
get = null;
alert("after get initvars");
alert("before call to initpage");
addLoadEvent(initVars());
</script>
I've used the htmldb_Get with success for populating other global variables and running On Demand Processes with onchange JS calls in the html form element attributes within select lists on the page. Afterwards, I can check the globals via the Session window and searching on Application Items. Unfortunately, I'm missing something because my G_CLASSIFICATION_ID_NEW never gets populated when I load the page. The alerts all popup when the page is loaded, so I know the script is being executed when the page loads. the alert(gReturn.value) comes back undefined. And, needless to say, the G_CLASSIFICATION_ID_NEW to 0 is not occurring.
I've tried the htmldb_Get with it calling an application process and without (set to null). From what I've read, you shouldn't need to call an on demand process to have the get.add set the global variable. Then again, this could be where I'm going wrong. however, as I've mentioned, this works for other functions called from an onchange to populate an application item, but the page has already loaded when the onchange(s) get executed. They may work because the page is already loaded when the onchange is called. My point here is that my other On demand processes are NOT setting or changing the global variables at all. The globals are getting set with the get.add(<app item>, <value>) portion of my other JS functions within the HTML Header region. So, I'm inclined to believe that I don't need the 'application_process=<some_odp>' parameter set, but if that's not true, please let me know. if so, what would need to be in the on demand process--ie, what would be the purpose of the get.add(<application item>, <value>) if I set the global variable in the on demand process because that's the only thing I could think of doing within an on demand process for this?
If somebody can point out what I'm not understanding or failing to do here, that would be great. I'm doing fine with APEX, but wouldn't consider myself a guru with it just yet. I'm definitely not a JS/AJAX guru, and when things like this go astray, I get bogged down because I'm not sure of the problem. So, I'm hoping you gurus who monitor this forum can get me going in the right direction.
thanks,
bob

Answer 1

Hi Jari,
Does that javascript work if you place it some of region footer on page 22 ?Yes. I cut it out of the html header of the page, and put it in the footer of the first region on the page. It initializes the variable. Putting it into the footer of the first region on the page should work for me instead of having an extra region on the page that's being picked up from page 0.
Is your page 22 authentication public ?No. This particular page is set for an ADMINISTRATOR only. That said, I am logged in as an administrator. So, I cannot see why setting authentication should make a difference as long as I have that authentication/authorization. Also, there will be other pages where I want to use this script or a similar script, but again, those pages will not be open to the public. the authentication will be "role" based where a user will not necessarily have to be an administrator, but they will have to have a certain role to access the page. Is there a known problem or something that precludes a html header JS script from doing an addloadevent when authentication is NOT public?
thank you,
bob