<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<style>
.box {
width: 50px;
height: 50px;
background: url(images/bgs.png) no-repeat -159px -51px;
position: fixed;
right: 10px;
top: 40%;
}
.erweima {
position: absolute;
top: 0;
left: -150px;
}
.box a {
display: block;
width: 50px;
height: 50px;
}
.hide {
display: none;
}
.show {
display: block;
}
</style>
</head>
<body>
<div class="box" id="box">
<div class="erweima hide" id="er">
<img src="images/456.png" alt=""/>
</div>
</div>
<script src="common.js"></script>
<script>
// 获取元素
var box = my$("box");
var er = my$("er");
// 给 box 添加鼠标移上事件 onmouseover ，添加鼠标离开事件 onmouseout
box.onmouseover = function () {
// 让子级元素进行显示，就是将 hide 改为 show
// er.className = "erweima show";
er.className = er.className.replace("hide","show");
};
box.onmouseout = function () {
// 让子级元素进行隐藏，就是将 show 改为 hide
// er.className = "erweima hide";
er.className = er.className.replace("show","hide");
};
</script>
</body>
</html>
