jQuery验证——在运行时更改max值

I have these validation rules:

我有这些验证规则:

$("#ed_details").validate({
    rules: {
        tagno: { required: true },
        itemid: { required: true },
        ralno: { required: true },
        feet: { required: true, number: true, min: 0 },
        inches: { required: true, number: true, min: 0 },
        cms: { required: true, number: true, min: 0 },
        length: { required: true, number: true, max: $('#maxlength').val() },
        qty: { required: true }
    }
});
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