Working with Change Flags

You may find it useful to know, after a page with User Input elements has been submitted, whether or not any changes were made to their default values - did the user make any changes? This, for example, might let your code decide whether or not to take some action, such as updating a database record. Logi Info provides a "change flag" mechanism to let you make this determination. A "change flag" is simply a Request variable with a True or False value; an Input Hidden element is added to a Report definition to generate that value. Other User Input elements specify the Input Hidden element's ID in their Change Flag Element ID attributes. When the page is submitted, in the next Report definition or Process task, the request variable associated with the Input Hidden element will have a value of True if any changes to Input elements occurred. This change flag functionality relies on the DHTML "onChange" event supported by all browser. Prior to Logi Info v12.1, this event was used to the exclusion of other events, so you could not also use your own onChange event handler with elements implementing a Change Flag Element ID.

Support for multiple events is now available. When using a change flag, you may also add Event Handlers to User Input elements and they will be processed after the onChange events associated with setting the Input element change flags.