Is close button functionality

My understanding has always been that any button with the property 'Is close button = yes', would be triggered when a user navigates away from the form without pressing one of the buttons. However, reading up on this property, it seems that it is only triggered in pop-up forms when the user presses the 'X' button. I'm wondering if other people agree with me that this functionality could be expanded? My main issue with the current (lack of) functionality is that there are so many ways for a user to avoid manual validation checks. Example: When a user enters a certain form, I set a boolean to 'true'. When the user leaves the form, I want the boolean to be 'false' again. Aside from using a pop-up, I currently see no way of guaranteeing this will happen. When a user navigates away via the menu, for example, it's already out of my control. Any ideas? Or should I create a feature request to expand 'Is close button' to other 'unorthodox' methods of leaving the screen?
1 answers

Unfortunately there is simply no way of knowing this and this is one of the restrictions of a web application. The user can always navigate away, close his browser, his computer can crash, his internet connection can be lost, so applications built for the web should consider this in their design.