请问如何使用HTML5+CSS3实现粘性导航栏效果，不通过JS

Question

请问如何使用HTML加CCS实现下面这个功能呢

 <script src="jquery-1.11.1.min.js"></script>
<div  style="height:1900px;background:#FC0;margin-top:40px;position:relative;">
    <ul id="napppv" class="yungf">
        <li>导航栏项目一</li>
        <li>导航栏项目二</li>
        <li>导航栏项目三</li>
        <li>导航栏项目四</li>
        <li>导航栏项目五</li>
    </ul>

</div>

<script>
$(function(){
    var a = $('#napppv'),
        b =a.offset();
    $(document).on('scroll',function(){
        var c = $(document).scrollTop();
        if(b.top<=c){
            a.css({'position':'fixed','top':'0px'})
            }else{
                a.css({'position':'absolute','top':'300px'})
                }
        })
    })
</script>

Answer 1

http://www.jb51.net/css/136367.html