Updating screens dynamically

When a user changes a field on a screen, that change can trigger other immediate changes on the screen. For example:

When the user selects a country from a drop-down list, show or hide the appropriate address fields for that country.
If a total value changes, update the distribution of partial values to line items in a list view.
Based on other data, set whether a PCF widget is visible, editable, available, or required.
When a particular field is changed, run a Gosu expression.

You can configure most input and cell widgets to immediately post their change to the PolicyCenter server. The server then reevaluates the page using the posted value and identifies any changes to other screen widgets as a result. If any widgets or their values have changed, the server instructs the client browser to redraw them. This process is called post-on-change.

A post-on-change operation affects only the rendering of the screen in the browser. It does not commit any data changes.

To maximize the performance of a post-on-change operation, the server sends the browser updated HTML for only the objects on the screen that have changed. The browser then redraws only those objects, and does not need to redraw the entire screen.

If the recalculateOnRefresh property of a Variable on the page is set to true, a post-on-change event causes the variable to be recalculated.