Setting item session state using AJAX in APEX 5

You probably know about the old way how to do this with htmldb_Get JS object:

  var get = new htmldb_Get(null, $v('pFlowId'), null, 0);

  get.add('F_APP_ITEM', vNewItemValue);
  gReturn = get.get();

You can find more about "the old way" here.

But If you've read APEX 5 Release Notes carefully you know that htmldb_Get object is deprecated and it's moved to legacy.js - and you don't what to use legacy JS in your new, modern and shiny APEX 5 applications. You should use apex.server.process or apex.server.plugin for plugins.

So, how can you do it in APEX 5?
It's easy if you want to set current page item values to session state. For this you have a parameter pageItems which can be of type jQuery selector, jQuery or DOM object or array of item names that identifies the page items:

apex.server.process ('MY_PROCESS', 
  {
     pageItems: '#P1_DEPTNO,#P1_EMPNO'
  }, 
  {
    success: function(pData) { ... do something here ... }
  } 
);

But if you want to do some calculations before request or if you want to set application item value to session state you have to dig a bit deeper into the documentation where you can find that with pData parameter of AJAX requests you can set additional parameters that the wwv_flow.show procedure provides.

If you need to set session state of only one item (page or application) you can use parameters p_arg_name and p_arg_value:

apex.server.process ('MY_PROCESS', 
  {
     p_arg_name: 'F_APP_ITEM',
     p_arg_value: vNewAppItemValue
  }, 
  {
    success: function(pData) { ... do something here ... }
  } 
);

If you need to set session state of more than one item (page or application) you have to use parameters p_arg_names and p_arg_values where you have to pass JS array as parameter:

apex.server.process ('MY_PROCESS', 
  {
     p_arg_names: ['F_APP_ITEM','P1_DEPTNO'],
     p_arg_values: [vNewAppItemValue, vNewItemValue]
  }, 
  {
    success: function(pData) { ... do something here ... }
  } 
);

Enjoy!

Tested on APEX 5.0.4.00.12