[Codes] Trượt lên trượt xuống

.up{
background-image: url(http://i24.servimg.com/u/f24/13/54/69/46/vote_u10.png);
background-repeat: no-repeat;
padding-right: 30px;
margin-right: 5px;
float: left;
cursor: pointer;
height: 24px;
margin-bottom: 6px;
}

a.up{
background-position: right top;
text-decoration:none;
}

a.up:hover {
background-position: right bottom;
text-decoration:none;
}
.down{
background-image: url(http://i24.servimg.com/u/f24/13/54/69/46/vote_d10.png);
background-repeat: no-repeat;
padding-right: 30px;
margin-right: 5px;
float: left;
cursor: pointer;
height: 24px;
margin-bottom: 6px;
}
a.down{
background-position: right top;
text-decoration:none;
}
a.down:hover {
background-position: right bottom;
text-decoration:none;
}

<a class="up" href="#top" onmouseover="showtip(up);"
onmouseout="hidetip();" onclick="hidetip();"></a><a
class="down" href="#bottom" onmouseover="showtip(down);"
onmouseout="hidetip();" onclick="hidetip();"></a>

<span onmouseover="showtip('Lên đầu trang');"
onmouseout="hidetip();"><a class="up" href="#top"
onmouseover="showtip(up);" onmouseout="hidetip();"
onclick="hidetip();"></a></span><span
onmouseover="showtip('Xuống cuối trang');"
onmouseout="hidetip();"><a class="down" href="#bottom"
onmouseover="showtip(down);" onmouseout="hidetip();"
onclick="hidetip();"></a></span>