jQuery validations using jQuery validate plugin in a separate js file in asp.net not working [duplicate]

I am using jQuery validation plugin( latest version downloaded, added in my project) in asp.net project. The problem is, my validation rules are in a separate js file. So when I type in <%=textbox.UniqueID%> I get an error - Expected identifier, string or number. I added quotes to make it a string - "<%=textbox.UniqueID%>" and now its just viewed as a string - it does not get the unique id of the text box. But when I put these validations in .aspx page it's working fine but this is not I want, I want to put validations in separate js file

Here is what I have tried

filename: customscript.js

$("#form1").validate({

        rules: {
                <%= txtOtprId.UniqueID %>: //here I am getting error   Expected identifier, string or number
                {
                    required: true,
                    alphanumeric: true,
                    minlength: 12,
                    maxlength: 12
                },
                <%= txtName.UniqueID %>: //here i am getting error
                {
                    required: true,
                    lettersonly: true
                }
          }
      });