Javascript Confirm box dependent on results of query

Question

Hi
I'm using Apex version 3.2.1 and I'm looking for a way to do the following, any help much appreciated:
A javascript confirm box will appear when the user submits a page if the result of a query returns anything, the query would look something like this....
SELECT * FROM LINKEDPROJECTS
WHERE ENV_ID = :P18_ENV_ID
AND COMP_ID = :P18_COMP_ID
AND DATE_FROM <= to_date(:P18_DATE_TO, 'DD-MON-YY')
AND DATE_TO >= to_date(:P18_DATE_FROM, 'DD-MON-YY')
If it doesnt return any data the page will submit as normal, if it does return any data the confirm box will appear, and the message will also be driven by the result of a query.
So the message would be something like....
Project(s) +"Select NAME FROM PROJECTS WHERE ID IN (SELECT PROJ_ID FROM LINKEDPROJECTS WHERE ENV_ID = :P18_ENV_ID+
+AND COMP_ID = :P18_COMP_ID+
+AND DATE_FROM <= to_date(:P18_DATE_TO, 'DD-MON-YY')+
+AND DATE_TO >= to_date(:P18_DATE_FROM, 'DD-MON-YY')"+ have this environment booked on the dates you selected.  Do you want to continue with the booking?
Selecting yes submits the page, selecting no returns them to the page.

Answer 1

In a nutshell (and some pseudo code):
The button URL would look something like "javascript:beforeSubmit()" without quotes and where beforeSubmit is the name of your function.
The function would look something like:
function beforeSubmit() {
  var runQuery = new htmldb_Get(null,&APP_ID.,'APPLICATION_PROCESS=RunTheQuery',1);
  var result = runQuery.get();
  if (result = 0) {
    if (!apex.confirm('Submit page?")
      return;
  doSubmit('SUBMIT');
{code}
The application process, called "RunTheQuery" in this example, is a PL/SQL block that runs the query and return the value using the htp.prn function.
There are probably errors in the above as I just did this off the top of my head, and you will probably need to tweak it somewhat.  But hopefully you get the idea.
Mark