SuiteFlow (Workflow Manager) Reference: Before Record Load Trigger
The Before Record Load trigger is a Server Trigger that fires right before the data for a new record or an existing record is loaded into the application accessing NetSuite (e.g. Browser, Mobile App, Web Services, etc.). Those data may include UI form elements and can be referenced or altered before the application loads it.
Use this trigger to set default field values, control form elements, and perform pre-processing tasks before the data is delivered to the accessing application.
If an error occurs during this trigger, the data will not be loaded and an error page will be displayed.