Alert on AJAX connection failures

js/app.js

@@ -38,7 +38,7 @@ var App = React.createClass({
     });
   },
   componentWillMount: function() {
-    document.addEventListener('unhandledRPCError', (event) => {
+    document.addEventListener('unhandledError', (event) => {
       this.alertError(event.detail);
     });
 

js/lbry.js

@@ -31,7 +31,7 @@ lbry.jsonrpc_call = function (connectionString, method, params, callback, errorC
       if (errorCallback) {
         errorCallback(response.error);
       } else {
-        var errorEvent = new CustomEvent('unhandledRPCError', {
+        var errorEvent = new CustomEvent('unhandledError', {
           detail: {
             connectionString: connectionString,
             method: method,
@@ -48,6 +48,25 @@ lbry.jsonrpc_call = function (connectionString, method, params, callback, errorC
     }
   });
 
+  if (connectFailedCallback) {
+    xhr.addEventListener('error', function (event) {
+      connectFailedCallback(event);
+    });
+  } else {
+    xhr.addEventListener('error', function (event) {
+      var errorEvent = new CustomEvent('unhandledError', {
+        detail: {
+          connectionString: connectionString,
+          method: method,
+          params: params,
+          code: xhr.status,
+          message: 'Connection to API server failed'
+        }
+      });
+      document.dispatchEvent(errorEvent);
+    });
+  }
+
   xhr.open('POST', connectionString, true);
   xhr.send(JSON.stringify({
     'jsonrpc': '2.0',