In custom data entry form you can use JavaScript to create dynamic behavior and customizations. As an example, you can hide form sections based on specific user input for data elements, or show specific information when a form loads.
The DHIS2 data entry module provides a range of events which you can register for and use to perform actions at certain times. The events are registered on the document element. The jQuery event object and the data set identifier are always the first two arguments provided to the callback functions. The table below provides an overview of the events and when they are triggered.