The tabindex global attribute indicates that its element can be focused, and where it participates in sequential keyboard navigation (usually with the Tab key, hence the name).
<p>Click anywhere in this pane, then try tabbing through the elements.</p>
<label>First in tab order:<input type="text"></label>
<div tabindex="0">Tabbable due to tabindex.</div>
<div>Not tabbable: no tabindex.</div>
<label>Third in tab order:<input type="text"></label>