id 1. property of many tags ... Specifies the identifier for the tag. If there are multiple tags with the same identifier, and using the identifier as a reference to an object with that identifier, an error occurs. The identifier must start with the characters: AZ, or: az, and can consist of the following characters: (A-Za-z), digits (0-9), minus ("-"), underscore ("_"), colon ( ":"), dot (".").
2. property of the STYLESHEET object, returns the id of the corresponding STYLE tag. window.document.stylesheets (number) .href where "number" is a sequential number from 0 of the STYLE tag on the page.