HTMLOptionElement: index property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The read-only index property of the HTMLOptionElement interface specifies the 0-based index of the element; that is, the position of the <option> within the list of options it belongs to, in tree-order, as an integer. If the <option> is not part of an option-list, the value is 0.