my.html
<div><a href="#" class="tip">你好<span><k>哈哈哈哈</k></span></a></div>
my.css
.tip {
color:#1a772d;
text-decoration:none;
}
.tip:hover {
color:#000;
}
.tip span {
display:none;
}
.tip:hover span{
display: block;
background-color:#fff;
border: 1px solid #aa9;
position: absolute;
text-align:left;
height: 25px;
width: 76px;
top:40px;
left:20px;
padding-top:5px;
padding-right:1px;
padding-bottom:0px;
padding-left:0px;
}
.tip:hover span k {
color: #aaa;
padding:5px;
background-color: #fff;
text-align: center;
border:1px solid #aaa;
}