Some times a website hijacks your tab and won't allow you to close it unless you choose an option. If you choose yes or no then it install a virus or malware. In chrome you can just hold enter and then close window and if force closes browser window. Only option is to force close the entire browser window via the task manager or agree to the terms. I believe javascript should not prevent you from closing the browser tab/window or at least write an internal over ride that will terminate any script running in the browser in the current tab. Otherwise why did I choose to close it in the first place. There might be legitimate reason to allow this but you should offer an override. Also from a user stand point there are many people out there that have little to no information about how a browser or tech works. Someone like my dad who is over 50 years old and struggles to us the internet or smart phone. He would not know how to deal with this. Thus would end up installing the virus. Anyway I have yet to see anywhere this is a useful feature. Mostly used on bad websites. I don't want to disable javascript for the browser. I just want close a tab. just before submitting this I encountered one window that if closed it would open up 2 more tabs. All with the same problem. So if I was going to code this I would code as some kind of button you hold down on the keyboard or right click and then terminates the script in the tab and then closes the tab. Like force quit a program.