I m trying to validate to validate the input depends on other html element. If the other html is empty it should validate the input and if not the not valid.

This is my HTML:

<input id="oka_rijkregister_last" name="oka_rijksregisternummer_last" type="text">
<span id="oka_rijkregister_last_BtnVal" class="error_msg"></span>

I have a separate function on input which validate the input data, if data is not correct it displays the error message in span element else remains empty.

Here is my JS code which i am trying to validate depends on span element.

$("#myform").validate({
  rules: {
    oka_rijksregisternummer_last : {
    minlength: {
      param:17,
      depends: function (element) {
          if($("#oka_rijkregister_last_BtnVal").html() === "") {
            return true;
          }
          else {
            return false;
          }
      }
    }
   }
  }
});

My code is working till param 17 and rest it ignores. Can anyone help with this?

Thanks in advance.