Prepare test

html/test_02.04.20/resources/js/error.js

@@ -0,0 +1,12 @@
+function createError(errorMessage) {
+  const error = document.createElement("div");
+  error.setAttribute('class', 'error');
+  
+  const errorBold = document.createElement("b");
+  errorBold.innerHTML = 'ERROR:';
+  error.appendChild(errorBold);
+
+  errorBold.after(errorMessage);
+
+  return error;
+}