jQuery validate with a dynamic number of fields

Question

I have a form with a stage that has a dynamic number of groups of fields, where the number is based upon answers in the previous stage.

I'm generating the fields server-side as an array, i.e.

<input id="foo[0]"...
<input id="bar[0]"...

<input id="foo[1]"...
<input id="bar[1]"...

<input id="foo[2]"...
<input id="bar[2]"... etc

No matter the number, all fields are required & I also need to validate against type & number of digits in some cases. I'm using the jQuery validate plugin for client-side processing (yes, backed up with server-side stuff too) & the validation can't be done inline as the form needs to pass XHTML Strict (EDIT: see my addendum below).

My problem is that I can't work out how to use validate with a dynamic number of fields. Here's what the validate syntax typically looks like for the rest of the form:

$(document).ready(function() {

    // validate stage_form on keyup and submit
    var validator = $("#form_id").validate({

        // rules for field names
        rules: {

            name: "required", 
            address: "required",
            age: { required: true, number: true }

        },

        // inline error messages for fields above
        messages: {

            name: "Please enter your name", 
            address: "Please enter your address",
            age: { required: "Please enter your age", number: "Please enter a number" }

        }

    });

});

Answer 1

Here is another way to do this.

/* Normal validate initialisation. */
$('#myForm').validate({

    /* Use the submitHandler method to add custom-selector-based validation. */
    submitHandler: function(form, ev) {

        /* Find your dynamic field/s. Note that you may want to access them via a scope external to validate, as any selection you do in this internal scope will be static from the form's pre-edit state. */
        var el = $('#selector');

        /* Do your custom validation. */
        if (  el.val() !== 'A'  ) {

            /* Show any errors:- 'fieldname': 'error message'. */
            this.showErrors({
                'name-of-a-field-near-where-you-want-your-error-placed': 'Please enter "A" to continue'
            });

            /* Prevent form submission. */
            return;
        } 
    }
});

Answer 2

No answers so I'll post my "interim" solution, which is to set inline validation rules for 'required' and 'type', leaving 'maxlength' to server-side checking, then display custom messages with an inline title tag.

This is probably good enough for the purposes of this job, but I'm still curious if there's a way to do it 'completely' within jQuery.

Answer 3

actually it should work If you'd use classes instead of initializing rules as validate() options.

Markup:

<input id="foo[0]" class="required"
<input id="bar[0]" class="required number"

<input id="foo[1]" class="required"
<input id="bar[1]" class="required email"

jQuery:

$(document).ready(function() {

  var validator = $("#form_id").validate({
    messages: {
            name: "Please enter your name", 
            address: "Please enter your address",
            age: { 
               required: "Please enter your age", 
               number: "Please enter a number" 
            }

    }

  });

});

hope this works. Sinan.

Answer 4

Have you tried to use custom class rules to define the xhtml incompatible rules?

The example in the docs only uses one class, but I suppose you could combine different custom classes to achieve the validation rules you need. I haven't tried this for myself.

Answer 5

I found a way to do using "metadata".

This should be used inside a template with a dynamic name. So, i don't need to know the name.

The downside is still not possible to use the code with pure javascript with clean tags.

<script src="jquery.metadata.js" type="text/javascript"></script>

<input validate="{required: true, email: true, messages: { required: 'i'm required', 'i'm not valid e-mail' }}" name="dynamicRow[  myRandomNumber ]"type="text" class="input_normal" />

 $( function() {
     // setup stuff
     $.metadata.setType("attr", "validate"); 
});