Adds some banner ads.

Author: simonbrowndotje

_includes/footer_custom.html

@@ -0,0 +1,63 @@
+<script>
+    const ads = [
+        {
+            img: 'patreon.png',
+            href: 'https://patreon.com/structurizr',
+            expiry: new Date('2025-12-31')
+        },
+        {
+            img: 'j-on-the-beach.png',
+            href: 'https://www.jonthebeach.com/workshops/visualising-software-architecture-with-the-C4-model/',
+            expiry: new Date('2025-05-13')
+        },
+        {
+            img: 'trifork-nl.png',
+            href: 'https://trifork.nl/academy/our-courses/software-architecture-for-developers/',
+            expiry: new Date('2025-05-20')
+        },
+        {
+            img: 'ddd-europe.png',
+            href: 'https://ddd.academy/visualising-software-architecture/',
+            expiry: new Date('2025-06-02')
+        },
+        {
+            img: 'yow-melbourne.png',
+            href: 'https://yowcon.com/melbourne-2025/masterclasses/541/visualising-software-architecture-with-the-c4-model',
+            expiry: new Date('2025-12-02')
+        },
+        {
+            img: 'yow-sydney.png',
+            href: 'https://yowcon.com/sydney-2025/masterclasses/542/visualising-software-architecture-with-the-c4-model',
+            expiry: new Date('2025-12-09')
+        }
+    ];
+
+    function showAd(id) {
+        try {
+            var ad;
+            while (ad === undefined || ad.expiry < new Date()) {
+                const randomNumber = Math.floor(Math.random() * ads.length);
+                ad = ads[randomNumber];
+            }
+
+            const img = document.createElement('img');
+            img.src = '/assets/ads/' + ad.img;
+            img.style.width = '728px';
+            img.style.height = '90px';
+            img.style.borderRadius = '5px';
+            img.style.border = 'solid 1px black';
+
+            const a = document.createElement('a');
+            a.href = ad.href;
+            a.target = '_blank';
+            a.append(img);
+
+            const mainContentElement = document.getElementById(id);
+            mainContentElement.insertBefore(a, mainContentElement.firstChild);
+        } catch (e) {
+            log.warn(e);
+        }
+    }
+
+    showAd('main-content');
+</script>