JSLint (prior to version 2013-03-18) throws the "ADsafe autocomplete violation" error when the adsafe and fragment options are both set to true (they're false by default) and you pass it a fragment of HTML that contains an input element with no autocomplete attribute whose value is off. Here's an example:
This error is raised when JSLint encounters code that violates the rules of the ADsafe subset of JavaScript. It is a fatal error that signifies a severe problem with ADsafe code and will have to be fixed before your ADsafe code will execute.
In a commit on 20th March 2013, HTML, CSS and ADsafe parsing functionality was removed from JSLint. If you rely upon this functionality, you will be unable to upgrade JSLint to a version beyond that date.