<tabindex>

The tabindex content attribute allows authors to control whether an element is supposed to be focusable, whether it is supposed to be reachable using sequential focus navigation, and what is to be the relative order of the element for the purposes of sequential focus navigation. The name "tab index" comes from the common use of the "tab" key to navigate through the focusable elements. The term "tabbing" refers to moving forward through the focusable elements that can be reached using sequential focus navigation.