Apexlib : "the" development framework for APEX

Apexlib is "the" development framework for the Oracle web development environment APEX (Oracle Application Express).
The framework makes use of the APEX repository, where all the information about the application is stored.
It enhances APEX by providing different new functionality which APEX currently doesn't offer. For example:

• Cascading Lovs (select lists and popup lovs) which use AJAX, so that no page roundtrip has to be done.
• Out-of-the-box Browser validation
• Access layer for tabular forms to handle the Apex_Application.g_fxx arrays
• Replacement of the APEX error page, to show the error as inline error message in the calling page and to highlight the column cell which has an error.
  and so on...

Get it and get it now :-)

Oh yeah...get it here http://apexlib.sourceforge.net/