html5判断当前浏览器页面选项卡是否被激活

html5判断当前浏览器页面选项卡是否被激活

作用

切换到别的选项卡，再切换回来的时候将会提示

 <script>
    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('页面非激活');
        alert("页面非激活");
    }else{
        console.log('页面激活')
        alert("页面激活");
    }
}
document.addEventListener(visibilityChangeEvent, onVisibilityChange);
</script>