Merge pull request #874 from andydale1982/U4-7323_(#871)‏

U4 7323 (#871)‏

src/Umbraco.Web.UI/Umbraco/js/install.loader.js

@@ -1,4 +1,5 @@
-LazyLoad.js( [
+try {
+    LazyLoad.js([
       'lib/jquery/jquery.min.js',
       /* 1.1.5 */
       'lib/angular/1.1.5/angular.min.js',
@@ -13,5 +14,11 @@ LazyLoad.js( [
         jQuery(document).ready(function () {
             angular.bootstrap(document, ['ngSanitize', 'umbraco.install', 'umbraco.directives.validation']);
         });
+    });
+}
+catch (err) {
+    if (err.message == 'LazyLoad is not defined') {
+        document.getElementById("feedback").style.display = "none";
+        document.getElementById("missinglazyload").style.display = "block";
     }
-);
+}

src/Umbraco.Web.UI/umbraco/Install/Views/Index.cshtml

@@ -45,7 +45,20 @@
         <p ng-bind-html-unsafe="installer.fact"></p>
     </div>
     
-    <h3 ng-cloak ng-animate="'fade'" id="feedback" ng-show="installer.feedback">{{installer.feedback}}</h3>     
+    <h3 ng-cloak ng-animate="'fade'" id="feedback" ng-show="installer.feedback">{{installer.feedback}}</h3> 
+   
+    <div id="missinglazyload" style="display: none;">
+        <h3>There has been a problem with the build.</h3> 
+        <p>This might be because you could be offline or on a slow connection. Please try the following steps</p>
+        <ol>
+            <li>Make sure you have <a href="https://nodejs.org" target="_blank">Node.js</a> installed.</li>
+            <li>Open command prompt and cd to \src\Umbraco.Web.UI.Client.</li>
+            <li>Check to see if \src\Umbraco.Web.UI.Client\node_modules folder exists (this could be hidden); if so delete it.</li>
+            <li>Run npm install; if successfull the node_modules folder should be created in the Umbraco.Web.UI.Client directory.</li>
+            <li>Run build\Build.bat.</li>
+        </ol>
+    </div>
+
     <script type="text/javascript">
         var Umbraco = {};
         Umbraco.Sys = {};