before gantt exits the fullscreen mode and goes back to normal mode
| boolean | defines whether the default action of the event will be triggered (true) or canceled (false) |
gantt.attachEvent("onBeforeCollapse",function(){
// any custom logic here
return true;
});
The event is blockable. Returning false will cancel further processing.
This event is defined in the fullscreen extension, so you need to activate the fullscreen plugin using the gantt.plugins method. Read the details in the Full Screen Mode article.