返回上一页

<a href="javascript:history.go(-1);">向上一页</a>

  response.Write("<script   language=javascript>")  
  response.Write("if(!confirm('您确定已经回复短信Y完成注册?')){history.back();}")  
  response.Write("</script>")  
  response.Write("<script   language=javascript>history.go(-1);</script>")

<a href="javascript:history.go(-1);">向上一页</a>