Hiding items on page entry if NULL in the database ...

Question

Environment: APEX 3.1.1.00.09
I have two (2) page items that I would like to hide in two (2) instances:
1- when the page is first displayed as the user is entering a new set of data
2- when the values of these items are NULL based on the fetched database row
I would like the items to display if the values in the row fetched are not NULL.
I already have logic that will hide the items based on specific values being selected or changed by the user but as requested in (1) above I would like the items to be hidden initially.
Be gentle as I'm still a newbie. :-)>
-gary

Answer 1

Hi Gary - I thought today was a public holiday in the US (something to do with a new president?)
Anyway..
You're correct - javascript is nothing to do with Apex, so debug doesn't even know it exists. The easiest way to test if your script is being run is to put alert('message') messages within the code:
function ...()
alert("Here 1");
alert("Here 2");
etcName the messages in a way that you can easily spot what is being run.
Perhaps it would be easiest for you if I explained what I did on my page (assuming that it is doing what you are trying to do? If not, just say).
On my page attributes, I have added the following into the HTML Header setting:
<script type="text/javascript">
function shA()
var l = document.getElementById('P6_LISTA');
if (l.value == 'A')
  $x_ItemRow('P6_TEXTA','SHOW');
else
  $x_ItemRow('P6_TEXTA','HIDE');
function shB()
var l = document.getElementById('P6_LISTB');
if (l.value == 'B')
  $x_ItemRow('P6_TEXTB','SHOW');
else
  $x_ItemRow('P6_TEXTB','HIDE');
</script>Strictly speaking, you could add this anywhere above the P6_xxx items - but the HTML Header is the best place to add javascript functions.
I then have four items on the page:
P6_LISTA - a select list
The Source is: STATIC:A,B,C,D,E
and the HTML Form Element Attributes setting is: onchange="javascript:shA();"
P6_LISTB - a select list
The Source is: STATIC:A,B,C,D,E
and the HTML Form Element Attributes setting is: onchange="javascript:shB();"
Both of these have Display Null: Yes - Null display value: -Select- and Null return value: Z
P6_TEXTA and P6_TEXTB are both normal text fields and have no special settings.
Finally, I have a region in the Before Footer display point and using "No Template" that has a Region Source of:
<script type="text/javascript">
shA();
shB();
</script>(this just runs the show/hide code on page load)
Does that help?
Andy