Add to cart works in Safari, not in Firefox or Chrome...

Yikes,

I haven't seen this before...

My add to cart button is only working in Safari... Any guidance on troubleshooting would be much appreciated...

My product template looks like this:

<div class="panel panel-default events-meta">
<div class="panel-heading">
    <h3 class="panel-title">Tickets:</h3>
</div>
<div class="panel-body">
<perch:form id="add_to_cart" app="perch_shop" class="cart nobottommargin clearfix" action="/cart" >

    <perch:if exists="has_variants">
            <div class="col_full">    
        <perch:input id="product" type="select" class="sm-form-control bottommargin-sm" env-autofill="false" options="<perch:shop id="_variant_opts" type="hidden" />" placeholder="Please choose" required="true" class="sm-form-control" />
            </div>
         <perch:else />
               <perch:input id="product" type="hidden" env-autofill="false" value="<perch:shop id="productID" type="hidden" />" />
    </perch:if>



    <div class="quantity clearfix" style="margin-right: 0px;">
        <div class="col_full nobottommargin">
        <perch:label for="qty">Quantity</perch:label>
        </div>
        <div class="col_full">
        <input type="button" id="sub" value="-" class="minus">
        <perch:input id="qty" value="1" class="qtyfull" />
        <input type="button" id="add" value="+" class="plus">
        </div>
    </div>
    <button class="button button-border button-circle button-dark col_full topmargin-sm"><i class="icon-shopping-cart"></i><span> Add to Cart</span></button>
    <perch:input type="cms" />

</perch:form>



<script>
$('.plus').click(function () {
    $(this).prev().val(+$(this).prev().val() + 1);
});
$('.minus').click(function () {
    if ($(this).next().val() > 0) $(this).next().val(+$(this).next().val() - 1);
});
</script>
</div>
</div>

My diagnostic looks like this:

Perch: 2.8.34, PHP: 5.6.29, MySQL: mysqlnd 5.0.11-dev - 20120503 - $Id: 76b08b24596e12d4553bd41fc93cccd5bac2fe7a $, with PDO
Server OS: Linux, cgi-fcgi
Installed apps: content (2.8.34), assets (2.8.34), categories (2.8.34), jw_activity_log (1.0.0), dh_ga (1), perch_blog (5.0), ui_checkout (1.0), perch_events (1.9.2), perch_forms (1.8.3), perch_gallery (2.8.6), perch_mailchimp (2.0.1), perch_newsfeed (1), perch_shop_orders (1.0.12), perch_shop_products (1.0.12), perch_shop (1.0.12), perch_comments (1.1), perch_members (1.5), pepperjack_tags (0.9), perch_backup (1.2), perch_twitter (3.5.1)
App runtimes: <?php $apps_list = array( 'content', 'categories', 'perch_blog', 'perch_events', 'perch_mailchimp', 'perch_forms', 'perch_twitter', 'perch_gallery', 'ui_checkout', 'perch_members', 'perch_shop', 'dh_member_profiles' );
PERCH_LOGINPATH: /perch
PERCH_PATH: /home/gmfgloucester/gloucestermeetinghouse.org/perch
PERCH_CORE: /home/gmfgloucester/gloucestermeetinghouse.org/perch/core
PERCH_RESFILEPATH: /home/gmfgloucester/gloucestermeetinghouse.org/perch/resources
Image manipulation: GD Imagick
PHP limits: Max upload 64M, Max POST 65M, Memory: 90M, Total max file upload: 64M
F1: 6a33f95eca3667f9e0c39bf5ca2980fe
Resource folder writeable: Yes
SCRIPT_NAME: /perch/core/settings/diagnostics/index.php
REQUEST_URI: /perch/core/settings/diagnostics/
DOCUMENT_ROOT: /home/gmfgloucester/gloucestermeetinghouse.org
HTTP_HOST: gloucestermeetinghouse.org