导航栏练习项目一

一：导航样式一

（一）html代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>导航样式一</title>
    <link rel="stylesheet" href="navigate.css">
    <script src="navigate.js"></script>
</head>
<body>
    <ul id="menu">
        <ul>
            <!-- center 包裹的元素居中 -->
            <center>
                <li><a href="#">唐</a></li>
                <li><a href="#">宋</a></li>
                <li><a href="#">元</a></li>
                <li><a href="#">明</a></li>
                <li><a href="#">清</a></li>
            </center>
        </ul>
    </ul>
</body>
</html>

（二）css代码

body{
margin: 0;
padding: 0;
background: #f1f1f1;
}
#menu{
margin: 0;
padding: 0;
margin-top: 150px;
}
#menu li{
    /* 变成行内块元素，在一行显示 */
    display: inline-block;
    list-style: none;
}

#menu li a{
    text-decoration: none;
    position: relative;
    color: #313131;
    font-size: 50px;
    font-weight: 700;
    font-family: sans-serif;
    display: block;
    overflow: hidden;
    /* 动画效果 */
    transition: 0.7s all;
    padding: 14px 20px;
    /* 控制文本中的字母，仅有大写字母*/
    text-transform: uppercase;
}
/* #menu li a:before{
    content: "";
    width: 50px;
    position: absolute;
    border-bottom: 8px solid #313131;
    bottom: 0;
    right: 100px;
    transform: 0.7 all;
}
#menu li a:hover:before{
    right: 0;
} */
#menu li a:hover{
    font-size: 70px;
    /* color: aqua; */
}

（三）js代码

window.onload = function(){
    var oUl = document.getElementById("menu");
    var aLi = oUl.getElementsByTagName("a");
    for(var i=0;i<aLi.length;i++){
        // 固定属性，一般循环中增加唯一标识都设这个值
        aLi[i].index = i
        aLi[i].onmouseover = function(){
            if(this.index==0){
                this.style.color="red";
            }else if(this.index==1){
                this.style.color="orange";
            }else if(this.index==2){
                this.style.color="yellow";
            }else if(this.index==3){
                this.style.color="green";
            }else{
                this.style.color="blue";
            }
           
        }
    }

}