javascript - Does the page visibility API actually support OS screen lock? -

according w3 page visibility specification , mozilla's page visibility api documentation, page visibility api supports detecting if browser window hidden because of os lock screen. unfortunately, of examples have found seem indicate not supported. cannot example js code or of js code report browser hidden when lock screen (on windows or os x).
of examples have tried:

• http://ie.microsoft.com/testdrive/performance/pagevisibility/default.html
• https://jsfiddle.net/wvupj/
• https://jsfiddle.net/fakj0puw/1/

none of these report page hidden when lock os. not supported though documentation indicates otherwise?

because have insert code able link jsfiddle...

var results = document.getelementbyid('results');  function handlevisibilitychange() {   if (document.webkithidden) {     results.innerhtml = results.innerhtml + 'hidden.<br>';   } else {     results.innerhtml = results.innerhtml + 'visible.<br>';   } }  document.addeventlistener("webkitvisibilitychange", handlevisibilitychange, false); 

it works on osx safari 8. (for lock , screen saver)

however no browser found works windows.

as of 27/04/2015