Process Ajax requests in struts

When I started the struts project, I used ajax to do some simple verification and use servlet for values, but this destroyed the original intent of struts MVC. However, due to its synchronization characteristics, the Struts framework was used, when submitting a page, the page will jump. Recently, I checked some information. If null is returned when the action is returned, the page Jump can be avoided. in this way, simple applications can use the Struts framework without compromising its features.
Public class demo {

Public actionforward execute (......){

...... Do your own work

// Finally, null is returned.

Return NULL;
}
}