Initial skeleton

static/js/utils.js

@@ -0,0 +1,18 @@
+function loadTemplateAsync(path) {
+  const result = new Promise(resolve => {
+    const xhttp = new XMLHttpRequest()
+
+    xhttp.onreadystatechange = function () {
+      if (this.readyState == 4) {
+        if (this.status == 200) resolve(this.responseText)
+
+        if (this.status == 404) resolve(`<div>Page not found: ${path}</div>`)
+      }
+    }
+
+    xhttp.open('GET', path, true)
+    xhttp.send()
+  })
+
+  return result
+}