jQuery Validation at least one checkbox is selected

Answer 1

Quote OP:

"I want to make sure that at least one of the check boxes is selected."

If you want to use the jQuery Validate plugin, and all checkboxes have a different name, simply use the require_from_group method that's part of the additional-methods.js file.

Since you already have a common class on these checkboxes called require-one, it's even easier.

$('#form').validate({
    rules: {
        fieldname: {
            require_from_group: [1, '.require-one']
        },
        // declare same rule on all eight checkboxes
        ....
        ....
    }
});

However, rather than declare all eight of these within .validate(), you can use the .rules('add') method inside of a jQuery .each() to declare them all at once.

$('.require-one').each(function () {
    $(this).rules('add', {
        require_from_group: [1, this],
        messages: {
            require_from_group: "please check one"
        }
    });
});

Then to combine all eight messages into one, use the groups option...

$('#form').validate({
    groups: {  // combine these error messages into one
        checkboxes: 'allwines beer redwines cider whitewines spirits sparkling fortified'
    }
});

Working DEMO: http://jsfiddle.net/JVWu2/1/

Placing your error message into the #error_msg3 error box is no different than placing any of your other jQuery Validate messages.