A 5250 screen specific thing we can do is to add scrolling buttons to a subfile it displays.

In the script associated with this example screen, three new functions could be added like this:

   /* Apply layout changes specific to this screen */

   ApplySpecificLayout : function()
   {
      if (CHECK_FIELD_EXISTS("PageDownMarker"))

HTMLAPI.insertSubFileScrollers("/ts/skins/images/pageup.gif",this.HandlePageUp,"/ts/skins/images/pagedown.gif",this.HandlePageDown,9,9,-46,82);
      else

 HTMLAPI.insertSubFileScrollers("/ts/skins/images/pageup.gif",this.HandlePageUp,null,null,9,9,-46,82);
   },

   /* Handle clicks on the subfile scroller images images */

   HandlePageDown: function() { EXECUTE_BUTTON_SCRIPT(KeyPageDown); },

   HandlePageUp: function()   { EXECUTE_BUTTON_SCRIPT(KeyPageUp); },

And the arrival script part of the screen definition is modified to invoke this new logic every time a screen arrives:

   vHandle_ARRIVE: function(oPayload, oPreviousForm)
   {
     var bReturn = true;

     /* If the department input field exists on the screen, display it */

     if ( CHECK_FIELD_EXISTS("DEPTMENT") )
     {

        SHARED.ApplyStandardLayout();
        this.ApplySpecificLayout();

etc, etc

When executed the example 5250 screen now looks like this: 
 

 
Note the page up and down clickable images appearing at the bottom of the subfile. When clicked they invoke the handler functions HandlePageUp and HandlePageDown, which then send page up / down keystrokes to the server.