What Is HTML Apex?

The goal of this article is to highlight how APEX actually processes the data that is sent data from the browser to the server when a submit button is pressed.

Stripping out a lot code, the underlying HTML code for this page looks like:

<form action="form.accept" id="Form" method="post" name="form">
<input name="p_arg_names" type="hidden" value="1234567891" />
  <input id="P1_FIRST_NAME" name="p_t01" type="text" value="" />

  <input name="p_arg_names" type="hidden" value="1234567892" />
  <input id="P1_LAST_NAME" name="p_t02" type="text" value="" />
</form>

You’ll notice that despite their being four input elements they’re really only three unique sets of names that are used: p_arg_names, p_t01, and p_t02. When the page is submitted the web server (APEX) will get/processes the following elements:

p_arg_names[1] = 1234567891
p_arg_names[2] = 1234567892

p_t01 = Name
p_t02 = Surname

None of the data sent back to the server make reference of P1_FIRST_NAME or P2_LAST_NAME. As well, p_arg_names is stored in a top down order of how they are in the page.

p_arg_names values are actually the IDs for each of the of the page items as highlighted in the following query:

select item_id, item_name
from apex_application_page_items
where 1=1
  and application_id = 118
  and page_id = 1;

ITEM_ID           ITEM_NAME
----------------- -------------
1234567891      P1_FIRST_NAME
1234567892      P1_LAST_NAME

APEX is able to map the data back to their corresponding APEX items by first mapping the values in p_arg_names to the apex_application_page_items view and then using the values in the p_txx to retrieve the data that was submitted for each item.

The order that the values are submitted in for p_arg_names must match the p_txx values for APEX to correctly map the values to their appropriate APEX item. I.e. p_args_names[1] will link to p_t01 and p_arg_names[2] will link to p_t02 etc.