pui.setPSHBTNFLD( field id, button )
This function emulates the PSHBTNFLD keyword by responding with a choice number.  The choice number is derived from the id of the button being pressed.  The screen is automatically submitted when this function is called.
Parameters:
field id - id of a hidden element bound to the PSHBTNFLD response field
button - reference to a button element that is being pressed
Example:
The following snippet of code would typically be assigned to the button's onclick event:
pui.setPSHBTNFLD("BUTTONS", this);