用Validator验证密码,minlength时候出错

Question

注册的时候对账号 密码验证，username 最小长度和最大长度都成功，password不论打入多少字符，都提示少于6个字符。为什么啊
<formset>
<form name="regForm">
  <field property="username" depends="required,minlength,maxlength">
    <arg0 key="namelab"/>
    <arg1 key="${var:minlength}" name="minlength" resource="false"/>
    <arg2 key="${var:maxlength}" name="maxlength" resource="false"/>
       <var>
            <var-name>maxlength</var-name>
            <var-value>15</var-value>
       </var>
       <var>
            <var-name>minlength</var-name>
            <var-value>6</var-value>
      </var>
 </field>
   <field property="password" depends="required,mask,minlength,maxlength">
        <arg0 key="passlab"/>
        <arg1 key="${var:minlength}" name="minlength" resource="false"/>
        <arg2 key="${var:maxlength}" name="maxlength" resource="false"/>
                <var>
                        <var-name>mask</var-name>
                        <var-value>^[0-9a-zA-Z]*$</var-value>
                </var>
                <var>
                         <var-name>minlength</var-name>
                         <var-value>6</var-value>
                </var>
                <var>
                         <var-name>maxlength</var-name>
                         <var-value>15</var-value>
                </var>
  </field>
<field property="password_s" depends="validwhen">
                <arg key="password2" />
                <var>
                    <var-name>test</var-name>
                    <var-value>(password==*this*)</var-value>
                </var>
                <msg name="validwhen" key="errors.password2"/>
            </field></form>
</formset>