[1] Web Tracking Protection ( ( 版)) http://www.w3.org/Submission/2011/SUBM-web-tracking-protection-20110224/
[2] navigator.doNotTrack - MDN ( ( 版)) https://developer.mozilla.org/en/DOM/navigator.doNotTrack
[3] 887703 - Do not track settings results in wrong value for navigator.doNotTrack () https://bugzilla.mozilla.org/show_bug.cgi?id=887703
The value reflects that of the do-not-track header, i.e. values of {"1", "0", "unspecified" }. Note: Prior to Gecko 32, Gecko used the values { "yes", "no", "unspecified"}
[2] Internet Explorer 9 and 10 use a vendor prefix, i.e. navigator.msDoNotTrack.
[3] Internet Explorer 11 uses window.doNotTrack rather than navigator.doNotTrack.
[4] Safari 7.1.3+ uses window.doNotTrack rather than navigator.doNotTrack.