//	导航固定在顶部
$(function() {
    //获取要定位元素距离浏览器顶部距离，100px
    var div2h = $('.banner').offset().top;
    console.log(div2h)
    //滚动条事件
    $(window).scroll(function() {
        //获取滚动条到顶部的滑动距离,滚动条到顶部的距离并不是实际的px数，如果是100px，则比实际网页中的100px要小
        var scroh = $(window).scrolltop();
        //滚动条的滑动距离大于等于定位元素距离浏览器顶部的距离，就固定，反之就不固定
        if (scroh >= div2h) {
            $(".nav").css({
                "position": "fixed",
                "top": 0,
                'background':'#fff'
            });
        } else if (scroh < div2h) {
            $(".nav").css({
                "position": "absolute"
            });
        }
    })
})

$(document).ready(function(){
    $(window).scroll(function(){
        if($(window).scrolltop()>80){
            $(".nav").css({
                "position": "fixed",
                'background':'#fff'
            });
            $('.logo').attr('src','http://www.ldxzb.com/uploads/20201106/87ad21043b00fb861087abc16b953301.png');
            $('.nav_ul a').css('color','#333');
        }else{
            $(".nav").css({
                "position": "fixed",
                "top": 0,
                'background':'rgba(0,0,0,0.2)'
            });
            $('.logo').attr('src','http://www.ldxzb.com/uploads/20201106/158dbc8d7852540e51d7314edb8f9f92.png');
            $('.nav_ul a').css('color','#fff');
        }
    })
    $(".nav_ul li").hover(function(){
        $(this).find('.nav_dl').css("display","block");
    },function(){
        $(this).find('.nav_dl').css("display","none");
    });
})