<!-- 把下列代码加入到head区内 -->
<style>
#borderlinks a{
padding-left: 4px;
display: block;
width: 150px;
color: black;
text-decoration: none;
border: 1px solid white;
}

#borderlinks a:hover{
border: 1px solid black;
background-color: lightyellow;
}

<!-- 把下列代码加入到body区内 -->
<div id="borderlinks">
<a href="http://www.alixixi.com">alixixi.com</a>
<a href="http://www.sina.com/">sina.com</a>
<a href="http://www.google.com">Google</a>
<a href="http://www.yahoo.com">Yahoo</a>
</div>