Tip of the day: hide (or show) multiple buttons or other page components with a single dynamic action

Need to hide or show multiple buttons or page items basing on a common client-side condition?

Instead  of creating a single dynamic action for each button, define a common CSS class (i.e. mybuttons) on each of the buttons and then use a single DA with jQuery selector like ".mybuttons" for the Hide action and one for the Show action, thus reducing the page complexity.

 

And you can also extend this to other components like page items or regions, if they follow the same logic.

Error: parsererror - SyntaxError: JSON.parse: unexpected non-whitespace character after JSON data at line 2 column 1 of the JSON data

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Error: parsererror - SyntaxError: JSON.parse: 

unexpected non-whitespace character after JSON data at line 2 column 1 of the JSON data

You may get this self-explanatory error at run-time if you specified a non-existing page item in the list of items to be returned after invoking a PL/SQL procedure from within a dynamic action in Oracle Application Express.

This may easily happen if you mistyped the page item name for instance, but in my case I had completely forgotten to create the item P4_ID.
Luckily I had an epiphany before going totally nuts.