jQuery validate - set conditional rules based on user selection

Question

Is it possible to easily setup a conditional rule with jQuery validate,

Simply put i'm trying add some logic which says, if checkbox 'A' is ticked - then field 'A' must be completed, if checkbox 'B' completed then fields 'B1' & 'B2' must be completed.

e.g if a checkbox with the name 'paypal' is checked - then the field named 'paypal_address' must be completed.

My existing logic is as follows:

<script type="text/javascript">
$(document).ready(function () {

$('#checkout-form').validate({
    rules: {
        first_name: {
            minlength: 2,
            required: true
        },
        last_name: {
            minlength: 2,
            required: true
        },
        address_1: {
            minlength: 2,
            required: true
        },
        address_2: {
            minlength: 2,
            required: true
        },
        post_code: {
            minlength: 2,
            required: true
        },            
        email: {
            required: true,
            email: true
        },
        terms: {
          required: true,
        }
    },
    errorPlacement: function(error, element) { 
      element.addClass('error');
    },        
    highlight: function (element) {
        $(element).addClass('nonvalid')
          .closest('.form-group').removeClass('error');
    },
    success: function (element) {
        //element.addClass('valid')
          //.closest('.form-group').removeClass('error');
          element.remove('error');
    }
});

UPDATE

Using the method below from Rohit i've almost got this working perfectly.. My form has three checkboxes (only one can be selected) 1. Paypal 2. Bank 3. Check/Cheque

If Paypal is checked (by default it is) then only have the 'paypal_email_address' field required, if Bank is checked then 'account_number' & 'sort_code' fields are required & finally if Cheque is checked the 'check_payable_field' is required.

// i've got this so far $( ".paymentMethod" ).on( "click", function() { var payment_method = $(this).val();

  if (payment_method == 'paypal') {
    paypal_checked = true;
  } else if (payment_method == 'bank-transfer') {
    bank_checked = true;
    paypal_checked = false;
  } else if (payment_method == 'cheque') {
    cheque_checked = true;
    paypal_checked = false;
  }

});

Answer 1

jQuery Validate actually directly supports this, using dependency expressions.

All you need to do is change your validate options like this:

$('#myform').validate({
    rules: {
        fieldA: {
           required:'#checkA:checked'
        }
    }
});

That's it!