Detect AJAX call failures

1 files changed, 13 insertions, 2 deletions

diff --git a/lib/js/urweb.js b/lib/js/urweb.js
index 9dd4dbbe..bfca94a4 100644
--- a/lib/js/urweb.js
+++ b/lib/js/urweb.js
@@ -133,8 +133,19 @@ function rc(uri, k) {
   var xhr = getXHR();
 
   xhr.onreadystatechange = function() {
-    if (xhr.readyState == 4)
-      k(xhr.responseText);
+    if (xhr.readyState == 4) {
+      var isok = false;
+
+      try {
+        if (xhr.status == 200)
+          isok = true;
+      } catch (e) { }
+
+      if (isok)
+        k(xhr.responseText);
+      else
+        alert("Error querying remote server!");
+    }
   };
 
   xhr.open("GET", uri, true);