Version: 4.0
The id core attribute is used to assign a name or id to a tag. This id must be unique within the document and can only be assigned to one use of a tag.
Because it is unique, the name of the id can be the target of a URL or used to define a style rule.
The use of id does not effect the output in any manner.
<input type="checkbox" id="ckbx1">
<input type="checkbox" id="ckbx2">