JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://ajax.aspnetcdn.com/ajax/jquery.validate/1.11.0/jquery.validate.min.js"></script>
<form action="#" class="send_form" id="forgot_pass_form" method="POST">
    <fieldset>
        <div class="send_row">
            <label class="padding-top10">Email</label>
            <input type="text" class="send_email send" id="email" name="email"
            /> <em>You need to type an email address</em>

        </div>
        <div class="send_row option">OR</div>
        <div class="send_row">
            <label class="padding-top10">Username</label>
            <input type="text" class="send_username send" id="uname"
            name="uname" />
        </div>
        <div class="send_row send_submitforgotuser">
            <input type="submit" value="Submit" />
        </div>
    </fieldset>
</form>
<a id="docs" href="http://docs.jquery.com/Plugins/Validation" target="_blank">Validation Documentation</a>

CSS

#docs {
    display: block;
    position: fixed;
    bottom: 0;
    right: 0;
}

JavaScript

$(document).ready(function () {

    jQuery.validator.addMethod("require_from_group", function (value, element, options) {
        var numberRequired = options[0];
        var selector = options[1];
        var fields = $(selector, element.form);
        var filled_fields = fields.filter(function () {
            // it's more clear to compare with empty string
            return $(this).val() != "";
        });
        var empty_fields = fields.not(filled_fields);
        // we will mark only first empty field as invalid
        if (filled_fields.length < numberRequired && empty_fields[0] == element) {
            return false;
        }
        return true;
        // {0} below is the 0th item in the options field
    }, jQuery.format("'Please enter either username/ email address to recover password'/Please fill out at least {0} of these fields."));

    $('#forgot_pass_form').validate({ // initialize the plugin
        groups: {
            names: "uname email"
        },
        rules: {
            uname: {
                require_from_group: [1, ".send"]
            },
            email: {
                require_from_group: [1, ".send"]
            }
        }
    });



});