<input type="button" onClick=urlchange() value="返回" style="background:#ffffff;font-size:10pt;color:#3300cc;">
<script>
function urlchange()
{
location.href='/servlet/HelloServlet?command=hello';
}</script>
<script>
function urlchange()
{
location.href='/servlet/HelloServlet?command=hello';
}</script>
或者
<input type="button" onClick='self.location.href="/servlet/HelloServlet?command=hello";' value="返回" style="background:#ffffff;font-size:10pt;color:#3300cc;">