var hiddenProperty = 'hidden' in document ? 'hidden' :
    'webkitHidden' in document ? 'webkitHidden' :
        'mozHidden' in document ? 'mozHidden' :
            null;
var visibilityChangeEvent = hiddenProperty.replace(/hidden/i, 'visibilitychange');
var onVisibilityChange = function(){
    if (document[hiddenProperty]) {
        console.log('頁面非啟用');
    }else{
        console.log('頁面啟用')
    }
}
document.addEventListener(visibilityChangeEvent, onVisibilityChange);