密码框不允许复制，只能包括英文字母数字下划线

jQuery.validator.addMethod("alnum", function(value, element) {
return this.optional(element) || /^[a-zA-Z0-9_]+$/.test(value);
}, "只能包括英文字母数字下划线");

$("#form1").validate({
rules:{
adminName:{
required: true,
minlength: 2,
maxlength: 10
},
realname:{
required: true,
stringCheck: true
},
pwd:{
required: true,
minlength: 8,
maxlength: 20,
alnum:true
}
},
messages:{
adminName:{
required: "请填写用户名",
minlength:"用户名最少为2个字符",
maxlength:"用户名最长为10个字符"
},
realname:{
required: "请填写姓名",
stringCheck: "请正确输入姓名"
},
pwd:{
required:"请填写密码",
minlength:"密码最少为8个字符",
maxlength:"密码最多为20个字符",
alnum:"只能包括英文字母数字下划线"
}
},
submitHandler:function(form){
       //在Submit之前，且所有驗證成功。
       $("#password-md5").val(hex_md5($("#password").val()));
prepareConfirm();
showLayer('lightBox-1');
       return false;
    }

});

   
   <tr>

  <td>初始密码：</td><td><input type="text" class="search_txt" name="pwd" id="password" οncοpy="return false" οnpaste="return false"/>
    <input type="hidden" class="search_txt" name="password" id="password-md5"/></td>
   </tr>