SIA-R3`id` attributes have a unique value

Accessibility requirements

This rule is not required for conformance to any accessibility requirements.

This rule checks that id attributes have a unique value.

This rule applies to every id attribute with a value that is not empty.

The value of the attribute is unique across all other id attributes specified on elements that exist within the same document tree or shadow tree as the element on which the applicable id attribute is specified.

This rule makes no assumptions.

This rule has no known accessibility support concerns.

These elements all have a different ids and therefore pass the rule:

<div id="my-div1">This is my first element</div>
<span id="my-div2">This is my second element</span>
<svg id="my-div3">This is my third element</svg>

These elements have the same id and therefore fail the rule:

<div id="my-div">This is my first element</div>
<span id="my-div">This is my second element</span>

This element has no id and is therefore inapplicable:

<div>This is my first element</div>