jquery validation error multiple fields 1 custom error message

Question

I've looked around on Stack to try and find a solution to a problem that I've encountered with my jQuery validation. I've decided to change my error messages, that were below my input fields to a single generic all encompassing message placed above the form. I have a class "hide" on that message "#error_mail" that I want to replace with "error" when there is an error in the field(s) on submission/validation. Any help would be greatly appreciated, thanks in advance.

HTML

<form action="#" method="post" class="new_web_user" id="new_web_user" autocomplete="off">
            <p class="fields-required">
            *Required fields</p>
            <p id="error_mail" class="hide">We&#39;re sorry, the fields highlighted in red are required</p>
            <div class="field-column"> etc etc.....

JS

$(function(){jQuery.validator.setDefaults({
             errorContainer: "#error_mail",
             errorPlacement: function(error, element) {
             error.appendTo('#error_mail');
      },
             ignore: ':hidden:not([class~=selectized]),:hidden > .selectized, .selectize-control .selectize-input input'
      });

    $('#new_web_user').validate({
              rules: {
                  web_user_title: {required: true},
                  web_user_given_name: {
                    required: true
                 },
                  web_user_family_name: {
                    required: true
                 },                  
                  web_user_email: { 
                    required:   true,
                    email:      true
                 },
                 email_confirmation: {
                    required:   true,
                      equalTo: '#web_user_email'
                 },
                 web_user_country: {
                    required:   false,
                 },
              },
              messages : {
                 web_user_title:     {
                        required: "Please select a title."
                 },
                 web_user_given_name:    {
                        required: "Firstname is required."
                 },
                 web_user_family_name:   {
                        required: "Lastname is required."
                 },
                 web_user_email:     {
                        required: "Email address is required.",
                        email: "Email address seems invalid."
                 },
                 email_confirmation:     {
                        required: "Email address is required.",
                        equalTo: "Email addresses do not match."
                 },
                 web_user_country:   {
                        required: "Please choose your country."
                 }
             },
             submitHandler:  function(form) {
                $.ajax({

Answer 1

You can simplify this a lot, using the options available in jQuery Validate:

$("#new_web_user").validate({
    errorContainer: '#error_mail',
    errorLabelContainer: '#actual_errors',
    wrapper:'li',
    //your rules and messages here
});

Then, change your HTML to be something more like this:

<p id="error_mail" class="hide error">
  We&#39;re sorry, the fields highlighted in red are required 
  <ul id="actual_errors"></ul>
</p>

Note that instead of adding/removing the error class you want on #error_mail, just set it at all times, as it will only be visible when there is a problem...

See it working here: http://jsfiddle.net/cayjuwf4/