IE11 fails to properly parse empty tabindex attribute. While [tabindex=""] yields the DOM property value element.tabIndex === 0 (like Gecko, Blink, WebKit), but IE11 returns a weird DOM attribute value element.getAttribute('tabindex') === '-32768'. The same value is exposed to CSS as well, as input[tabindex="-32768"] is the matching selector. This is also true for IE12 (Windows 10 developer preview).