//详细地看代码注释
        <form id="frmV" method="get" action="#">
            <div id="divtest">
                <div class="title">
                    <span class="fl">表单验证插件</span> 
                    <span class="fr">
                        <input id="btnSubmit" type="submit" value="提交" />
                    </span>
                </div>
                <div class="content">
                    <span class="fl">邮箱：</span><br />
                    <input id="email" name="email" type="text" /><br />
                    <span class="tip"></span>  /*这里是错误信息提示的地方，错误信息放在span内，*/
                </div>
            </div>
        </form>
        
        <script type="text/javascript">
            $(function () {
                $("#frmV").validate(
                  {
                      /*自定义验证规则*/
                      rules: {
                            email:{
                                required:true,  /*必须填写*/
                                email:true      /*符合邮箱的格式*/
                          }
                      },
                     messages: {   //错误信息，不符合上面的rule验证要求时显示
                        email: {
                            required: "请输入Email地址",  
                            email: "请输入正确的email地址"
                        }
                       },
                      /*错误提示位置*/
                      errorPlacement: function (error, element) {
                          error.appendTo(".tip");  /*如果不符合验证要求，将错误信息，即上面的message信息插入到class为tip的元素span内*/
                      }
                  }
                );
            });
        </script>

详细地看这个文档 http://www.cnblogs.com/hejunrex/archive/2011/11/17/2252193.html