不行啊，大神们

源自：6-4 编程练习

不行啊，大神们

<!DOCTYPE html>

<html>

<head>

<title>地狗购物网——网页定位导航效果</title>

<style>

* {

margin: 0;

padding: 0;

}

body {

font-size: 12px;

line-height: 1.7;

}

li {

list-style: none;

}

#content {

width: 800px;

margin: 0 auto;

padding: 20px;

}

#content h1 {

color: #0088bb;

}

#content .item {

padding: 20px;

margin-bottom: 20px;

border: 1px dotted #0088bb;

}

#content .item h2 {

font-size: 16px;

font-weight: bold;

border-bottom: 2px solid #0088bb;

margin-bottom: 10px;

}

#content .item li {

display: inline;

margin-right: 10px;

}

#content .item li a img {

width: 230px;

height: 230px;

border: none;

}

/*请补充此处代码，让导航菜单在右侧绝对定位显示*/

#menu {

position :fixed;

top:100px;

left:50%;

margin-left:400px;

width:180px;

}

#menu ul li a {

display: block;

margin: 5px 0;

font-size: 14px;

font-weight: bold;

color: #333;

width: 80px;

height: 50px;

line-height: 50px;

text-decoration: none;

text-align: center;

}

#menu ul li a:hover,

#menu ul li a.current {

color: #fff;

background: #0088bb;

}

/*ie6 hack*/

* html, * html body {

background-image: url(about:blank);

background-attachment: fixed;

}

* html #menu {

/* position: fixed;*/

position: absolute;

top: expression(((e=document.documentElement.scrollTop)?e:document.body.scrollTop)+100+'px');

}

</style>

function getByClassName(obj,cls){

var elements = obj.getElementsByTagName(" * ");

var result = [];

for(var i=0;i<elements.length;i++){

if(elements[i].className == cls){

result.push(elements[i]);

}

}return result;

}

console.log(top);

function hasClass( obj, cls ){

return obj.className.match(new RegExp("(\\s|^)" + cls + "(\\s|$)"));

}

function removeClass( obj, cls ){

if( hasClass( obj, cls )){

//remove

var reg = new RegExp("(\\s|^)" + cls + "(\\s|$)");

obj.className = obj.className.replace(reg, "");

}

function addClass(obj,cls){

if(!hasClass(obj,cls)){

obj.className += " " +cls;

}

//定义getByClassName函数，让函数实现给对象增加class

window.onload = function(){

window.onscroll = function(){

var top = document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop;

var menus = document.getElementById("menu").getElementsByTagName("a");

var items = getByClassName(document.getElementById("content"), "item");

var currentId = "";

for ( var i=0; i< items.length; i++ ){

var _item = items[i];

var _itemTop = _item.offsetTop;

if( top > _itemTop - 200 ){

currentId = _item.id;

} else {

break;

}

//请补充此处代码，给正确的menu下的a元素class赋值current

if(currentId){

for(var j=0;j<menus.length;j++){

var _menu = _menus[j];

var _href = _menu.href.split("#");

if(_href[_href.length - 1] !=currentId){

removeClass(_menu ,"current");

}else{

addClass(_menu,"current" );

}

</script>

</head>

<body>

<ul>

</ul>

</div>

<h1>地狗购物网</h1>

<ul>

</ul>

</div>

<ul>

</ul>

</div>

<ul>

</ul>

</div>

<ul>

</ul>

</div>

<ul>

</ul>

</div>

</body>

</html>

提问者：慕粉1906006274 2017-02-07 01:13

个回答

慕粉18144024425

2017-02-07 23:15:33

已采纳

错在这行：var elements = obj.getElementsByTagName("*");
("*")，这个星号不能有空格，

0
慕粉18144024425

2017-02-07 23:16:18

var _menu = menus[j]; 还有这个

0
慕粉18144024425

2017-02-07 21:56:23

你代码很乱，要养成好习惯

0
慕粉18144024425

2017-02-07 21:55:34

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
<title>地狗购物网——网页定位导航效果</title>
<style>
* {
margin: 0;
padding: 0;
}

body {
font-size: 12px;
line-height: 1.7;
}

li {
list-style: none;
}

#content {
width: 800px;
margin: 0 auto;
padding: 20px;
}

#content h1 {
color: #0088bb;
}

#content .item {
padding: 20px;
margin-bottom: 20px;
border: 1px dotted #0088bb;
}

#content .item h2 {
font-size: 16px;
font-weight: bold;
border-bottom: 2px solid #0088bb;
margin-bottom: 10px;
}

#content .item li {
display: inline;
margin-right: 10px;
}

#content .item li a img {
width: 230px;
height: 230px;
border: none;
}

#menu {
position: fixed;
top: 100px;
left: 50%;
margin-left: 400px;
width: 80px;
}

#menu ul li a {
display: block;
margin: 5px 0;
font-size: 14px;
font-weight: bold;
color: #333;
width: 80px;
height: 50px;
line-height: 50px;
text-decoration: none;
text-align: center;
}

#menu ul li a:hover,
#menu ul li a.current {
color: #fff;
background: #0088bb;
}

/*ie6 hack*/
* html, * html body {
background-image: url(about:blank);
background-attachment: fixed;
}

* html #menu {
/*position: fixed;*/
position: absolute;
top: expression(((e=document.documentElement.scrollTop)?e:document.body.scrollTop)+100+'px');
}

</style>
<script>

//定义getByClassName函数，让函数实现根据class name获取对象并返回
function getByClassName(obj, cls){
var elements = obj.getElementsByTagName("*");
var result = [];
for(var i = 0; i < elements.length; i++){
if(elements[i].className == cls){
result.push(elements[i]);
}
}
return result;
}

function hasClass( obj, cls ){
return obj.className.match(new RegExp("(\\s|^)" + cls + "(\\s|$)"));
}

function removeClass( obj, cls ){
if( hasClass( obj, cls )){
//remove
var reg = new RegExp("(\\s|^)" + cls + "(\\s|$)");
obj.className = obj.className.replace(reg, "");
}
}

//定义getByClassName函数，让函数实现给对象增加class
function addClass(obj, cls){
if(!hasClass(obj, cls)){
obj.className += " " + cls;
}
}

window.onload = function(){

window.onscroll = function(){
var top = document.documentElement.scrollTop || document.body.scrollTop;

var menus = document.getElementById("menu").getElementsByTagName("a");

var items = getByClassName(document.getElementById("content"), "item");

var currentId = "";

for ( var i=0; i< items.length; i++ ){
var _item = items[i];
var _itemTop = _item.offsetTop;
if( top > _itemTop - 200 ){
currentId = _item.id;
} else {
break;
}
}

//请补充此处代码，给正确的menu下的a元素class赋值current
if(currentId){
for(var j = 0; j < menus.length; j++){
var _menu = menus[j];
var _href = _menu.href.split("#");
if(_href[_href.length - 1] != currentId){
removeClass(_menu, "current");
} else {
addClass(_menu, "current");
}
}
}

}
}
</script>
</head>
<body>
<div id="menu">
<ul>


<li><a href="#item1" class="current">1F 男装</a></li>
<li><a href="#item2">2F 女装</a></li>
<li><a href="#item3">3F 美妆</a></li>
<li><a href="#item4">4F 数码</a></li>
<li><a href="#item5">5F 母婴</a></li>
</ul>
</div>
<div id="content">
<h1>地狗购物网</h1>

<div id="item1" class="item">
<h2>1F 男装</h2>
<ul>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
</ul>
</div>
<div id="item2" class="item">
<h2>2F 女装</h2>
<ul>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/5366104c0001e5c403990422.jpg" alt=""/></a></li>
</ul>
</div>
<div id="item3" class="item">
<h2>3F 美妆</h2>
<ul>
<li><a href="#"><img src="http://img.mukewang.com/536610820001cf5b03990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610820001cf5b03990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610820001cf5b03990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610820001cf5b03990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610820001cf5b03990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610820001cf5b03990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610820001cf5b03990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610820001cf5b03990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610820001cf5b03990422.jpg" alt=""/></a></li>
</ul>
</div>
<div id="item4" class="item">
<h2>4F 数码</h2>
<ul>
<li><a href="#"><img src="http://img.mukewang.com/536610ac00012df703990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610ac00012df703990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610ac00012df703990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610ac00012df703990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610ac00012df703990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610ac00012df703990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610ac00012df703990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610ac00012df703990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610ac00012df703990422.jpg" alt=""/></a></li>
</ul>
</div>
<div id="item5" class="item">
<h2>5F 母婴</h2>
<ul>
<li><a href="#"><img src="http://img.mukewang.com/536610cd0001f34603990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610cd0001f34603990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610cd0001f34603990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610cd0001f34603990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610cd0001f34603990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610cd0001f34603990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610cd0001f34603990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610cd0001f34603990422.jpg" alt=""/></a></li>
<li><a href="#"><img src="http://img.mukewang.com/536610cd0001f34603990422.jpg" alt=""/></a></li>
</ul>
</div>
</div>
</body>
</html>

0
慕少5527016

2017-02-07 21:43:45

var _menu = menus[j];
其他问题没发现

0