@EncyKe
2016-01-04T02:17:52.000000Z
字数 3845
阅读 3132
前端
JavaScript
<!-- 滚动监视按钮 -->
<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>
<!-- 长页面主体 -->
<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="1F.jpg" alt=""/></a></li>...
</ul>
</div>
<div id="item2" class="item">
<h2>2F 女装</h2>
<ul>
<li><a href="#"><img src="2F.jpg" alt=""/></a></li>...
</ul>
</div>
<div id="item3" class="item">
<h2>3F 美妆</h2>
<ul>
<li><a href="#"><img src="3F.jpg" alt=""/></a></li>...
</ul>
</div>
<div id="item4" class="item">
<h2>4F 数码</h2>
<ul>
<li><a href="#"><img src="4F.png" alt=""/></a></li>...
</ul>
</div>
<div id="item5" class="item">
<h2>5F 母婴</h2>
<ul>
<li><a href="#"><img src="5F.jpg" alt=""/></a></li>...
</ul>
</div>
</div>
/* reset */
* {
margin: 0;
padding: 0;
}
body {
font-size: 12px;
line-height: 1.7;
}
li {
list-style: none;
}
/* 长页面内容样式 */
#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;
}
/* 滚动监视按钮样式 */
#menu {
position: fixed;
top: 100px;
left: 50%;
margin-left: 400px;
width: 50px;
}
#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;
}
/* IE 6 兼容 */
/* 防止IE 6 滚动跳变的写法 */
* html, * html body {
background-image: url(about:blank);
background-attachment: fixed;
}
* html #menu {
position: absolute;
bottom: auto;
top: expression(100+((e=document.documentElement.scrollTop)?e:document.body.scrollTop)+'px');
}
window.onload = function(){
window.onscroll = function(){
var top = document.documentElement ? document.body.scrollTop :document.documentElement.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;
};
};
if (currentId) {
for (var j = 0; j < menus.length; j++) {
var _menu = menus[j];
// href属性获取的是整个link,需以#为界截除获取最后一个元素;
var _href = _menu.href.split("#");
if (_href[_href.length - 1] != currentId) {
removeClass(_menu, "current");
}else{
addClass(_menu, "current");
};
};
};
}
}
/* 封装类名函数集:判断、移除、增加、获取(正则表达式版);
function hasClass(obj, cls){
return obj.className.match(new RegExp("(\\s|^)" + cls + "(\\s|$)"));
}
function removeClass(obj, cls){
if (hasClass(obj,cls)) {
var reg = new RegExp("(\\s|^)" + cls + "(\\s|$)");
obj.className = obj.className.replace(reg,"");
};
}
function addClass(obj, cls){
if (!hasClass(obj, cls)) {
obj.className += " " + cls;
};
}
*/
// 封装类名函数集:判断、移除、增加、获取(简单粗暴版);
function removeClass(obj,cls){
if(obj.className == cls) {
obj.className=""
};
}
function addClass(obj,cls){
if(obj.className != cls) {
obj.className = cls
};
}
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;
}
$(document).ready(function () {
$(window).scroll(function () {
var items = $("#content").find(".item");
var menu = $("#menu");
// 滚动条距离顶部的距离;
var top = $(document).scrollTop();
// 滚动条现在所在位置的item id;
var currentId = "";
// 遍历以获取高度;
items.each(function () {
var m = $(this);
// m.offset().top代表每一个item的顶部位置
if (top > m.offset().top - 300) {
currentId = "#" + m.attr("id");
} else {
return false;
}
});
var currentLink = menu.find(".current");
if (currentId && currentLink.attr("href") != currentId) {
currentLink.removeClass("current");
menu.find("[href=" + currentId + "]").addClass("current");
}
});
});