Bootcamp page: CTAs say 'Buy for 790 USD' and post the basket natively

The three CTAs (hero, mid-page, §7) were <a class="btn-buy"> that only worked
through JavaScript. They are now native <form method="post" target="_blank">
elements posting basket=[{"product_id":12,"qty":1}] + clear=1 to
https://20.odoo4projects.com/shop/post_basket, so the buy works with JavaScript
disabled; the button keeps the brass styling and the same size classes.

static/buy.js no longer builds a form on click. It is now pure progressive
enhancement: a capture-phase submit listener appends the utm_source/medium/
campaign hidden inputs from the cookies and lets the native submit proceed.

One page-scoped declaration keeps the button height at 55px: a <button> takes
line-height:normal from the UA font shorthand where the <a>s inherited the body
line-height (measured 49.19px vs 54.78px without it).

static/buy.js

@@ -1,10 +1,14 @@
-/* buy.js — page-local checkout helper.
+/* buy.js — page-local checkout helper (progressive enhancement).
  *
- * Mirrors `script.js` `buyNow()` — the main page's checkout path.
+ * The checkout itself is a native <form method="post" target="_blank"> that posts
+ * basket=[{"product_id":12,"qty":1}] + clear=1 to
+ * https://20.odoo4projects.com/shop/post_basket. With JavaScript off it still works.
+ *
+ * This file only adds attribution: on submit it appends the utm_* hidden inputs
+ * from the cookies, then lets the native submit proceed (it never preventDefault).
+ *
+ * The UTM helpers mirror `script.js` `buyNow()` — the main page's checkout path.
  * If that changes, change this too.
- *
- * Loaded by pages that do not load `script.js` (e.g. the bootcamp page).
- * Binds `.btn-buy` elements: <a class="btn-buy" data-id="12">…</a>.
  */
 (function () {
     'use strict';
@@ -29,7 +33,7 @@
         var stored = getStoredUTM();
         var keys = ['source', 'medium', 'campaign'];
         for (var i = 0; i < keys.length; i++) {
-            if (stored[keys[i]]) {
+            if (stored[keys[i]] && !form.elements['utm_' + keys[i]]) {
                 var input = document.createElement('input');
                 input.type = 'hidden';
                 input.name = 'utm_' + keys[i];
@@ -39,41 +43,13 @@
         }
     }
 
-    /* ---- Buy Now — POST basket via form, opens checkout in new tab ---- */
-    window.buyNow = function (productId) {
-        var form = document.createElement('form');
-        form.method = 'POST';
-        form.action = 'https://20.odoo4projects.com/shop/post_basket';
-        form.target = '_blank';
-        form.style.display = 'none';
-
-        var basket = document.createElement('input');
-        basket.type = 'hidden';
-        basket.name = 'basket';
-        basket.value = JSON.stringify([{ product_id: productId, qty: 1 }]);
-        form.appendChild(basket);
-
-        var clear = document.createElement('input');
-        clear.type = 'hidden';
-        clear.name = 'clear';
-        clear.value = '1';
-        form.appendChild(clear);
-
+    /* ---- Progressive enhancement: add UTM inputs to the native basket form ----
+       Capture phase, so the inputs are in the form before the browser serialises it.
+       No preventDefault — the native POST proceeds untouched. */
+    document.addEventListener('submit', function (e) {
+        var form = e.target;
+        if (!form || form.tagName !== 'FORM') return;
+        if (!form.querySelector('input[name="basket"]')) return;
         appendToForm(form);
-
-        document.body.appendChild(form);
-        form.submit();
-        document.body.removeChild(form);
-    };
-
-    /* ---- Bind .btn-buy (delegated: same contract as script.js) ---- */
-    document.addEventListener('click', function (e) {
-        var btn = e.target.closest ? e.target.closest('.btn-buy') : null;
-        if (!btn) return;
-        var id = btn.getAttribute('data-id');
-        if (id) {
-            e.preventDefault();
-            window.buyNow(parseInt(id, 10));
-        }
-    });
+    }, true);
 })();