Add dynamic, live alerts example to docs (#33866)

site/assets/js/application.js

@@ -58,6 +58,22 @@
     })
   }
 
+  var alertPlaceholder = document.getElementById('liveAlertPlaceholder')
+  var alertTrigger = document.getElementById('liveAlertBtn')
+
+  function alert(message, type) {
+    var wrapper = document.createElement('div')
+    wrapper.innerHTML = '<div class="alert alert-' + type + ' alert-dismissible" role="alert">' + message + '<button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button></div>'
+
+    alertPlaceholder.append(wrapper)
+  }
+
+  if (alertTrigger) {
+    alertTrigger.addEventListener('click', function () {
+      alert('Nice, you triggered this alert message!', 'success')
+    })
+  }
+
   // Demos within modals
   document.querySelectorAll('.tooltip-test')
     .forEach(function (tooltip) {