首先css解决一下ie6不支持position:fixed;的缺陷。
css
===
#menu {
position: fixed;
top: 100px;
left: 50%;
margin-left: 400px;
width: 50px;
}
* 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');
}
js:
$(document).ready(function () {
$(window).scroll(function () {
var items = $("#content").find(".item");
var menu = $("#menu");
var top = $(document).scrollTop();
var currentId = ""; //滚动条现在所在位置的item id
items.each(function () {
var my = $(this);
//m.offset().top代表每一个item的顶部位置
if (top > my.offset().top) {
currentId = "#" + my.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");
}
});
});
