timer = 0; function onLoad()( document.addEventListener("visibilitychange",stateChanged); document.addEventListener("webkitvisibilitychange", stateChanged); document.addEventListener("msvisibilitychange", stateChanged); ) function stateChanged()( console.log(document.webkitVisibilityState); if(document.hidden || document.webkitHidden || document.msHidden)( //new tab or window minimized timer = new Date().getTime(); ) else ( alert('You were away for ' + (new Date().getTime()-timer)/1000+ ' seconds.') ) ) Демо Сагара Ганатры