# ally.is.validTabindex
Determines if an element's tabindex attribute value is sound
# Usage
var element = document.getElementById('victim');
var isValidTabindex = ally.is.validTabindex(element);
# Arguments
| Name | Type | Default | Description |
|---|---|---|---|
| element | HTMLElement |
required | The Element to test. |
# Returns
Boolean, true if the element is has a valid tabindex attribute specified.
# Throws
TypeError if element argument is not of type HTMLElement.
# Changes
- Since
v1.4.0supportstabIndexas attribute name for SVG elements in Microsoft Edge.
# Notes
::note
Empty tabindex [tabindex=""] parsed and exposed as [tabindex="-32768"] - Trident 1072965.
:::
Invalid tabindex value makes element focusable in - Gecko 1128054.
Gecko, Blink and WebKit consider [tabindex="3x"] valid.