Horje

HTML - Tabindex
Start
  Add an element to the tabbing order 
<div tabindex="0">Some button</div>

Note: Try to use a native HTML button or an a tag where appropriate.
  Define a custom tabbing order (not recommended) 
<div tabindex="2">Second</div>
<div tabindex="1">First</div>

Positive values will insert the element at the tabbing order position of its respective value. Elements without preference (i.e. tabindex="0" or native elements such as button and a) will be appended after those with preference.

Positive values are not recommended as they disrupt the expected behavior of tabbing and might confuse people who rely on screenreaders. Try to create a natural order by rearranging your DOM structure.

Parameters

Value Meaning
negative element will be focusable, but it should not be reachable via sequential keyboard navigation
0 element will be focusable and reachable through keyboard sequential navigation, but it's relative order is defined by the platform convention
positive element must be focusable and accessible via sequential keyboard navigation; it's relative order will be defined by the attribute value: the sequential follow the increasing number of the tabindex

Remarks

The maximum value for tabindex should not exceed 32767 as per W3C section 17.11.1 Unless specified default value is -1

An element with a value of 0, an invalid value, or no tabindex value should be placed after the elements with a positive index in the sequential order of keyboard navigation.
  Remove an element from the tabbing order 
<button tabindex="-1">This button will not be reachable by tab</button>

The element will be removed from the tabbing order but will still be focusable.

 

Read Article
https://develop.horje.com/learn/1434/reference

 

Horje