js 设置 cookie 定时 弹出层 提示层 下次访问 不再显示 弹窗 getCookie setCookie setTimeout

<div class="index-tt"></div>

.index-tt {
    width: 100%;
    height: 100%;
    left: 0;
    top: 0;
    position: fixed;
    z-index: 66;
    background: url(../images/index-tt01.png);
    background-size: 100%;
    display: none;
}

<script>//遮罩层
console.log(getCookie('tt'));
if( getCookie('tt') != 7){

    setTimeout(function(){
        $('.index-tt').fadeIn();
        document.body.style.overflow='hidden';
        document.body.style.height='100%';
        document.documentElement.style.overflow='hidden';
        window.scrollTo(0,0);
    },3000);

}

    $('.index-tt').click(function(){
        $('.index-tt').fadeOut();
        document.body.style.overflow='auto';
        document.body.style.height='auto';
        document.documentElement.style.overflow='auto';
        setCookie('tt','7',10000);
    });

    function setCookie(c_name,value,expiredays)
    {
    var exdate=new Date()
    exdate.setDate(exdate.getDate()+expiredays)
    document.cookie=c_name+ "=" +escape(value)+
    ((expiredays==null) ? "" : ";expires="+exdate.toGMTString())
    }    


    function getCookie(c_name)
    {
        if (document.cookie.length>0)
        {
            c_start=document.cookie.indexOf(c_name + "=")
            if (c_start!=-1)
            { 
            c_start=c_start + c_name.length+1 
            c_end=document.cookie.indexOf(";",c_start)
            if (c_end==-1) c_end=document.cookie.length
            return unescape(document.cookie.substring(c_start,c_end))
            } 
        }
        return ""
    }

</script>