Demo:
Code:<style>div.footer_left {background:#333} .switch_pc {margin-top:15px} .switch_pc a{color:#ddd;border:1px solid #ddd;padding:2px 0;display:block} .switch_pc a:hover{text-decoration:none} </style><div class="footer_left"><div class="switch_pc" style="clear:both;"><small><a href="#top"><center>Back To Top</center></a></small></div></div>