diff --git a/weinre.web/modules/weinre/target/Target.coffee b/weinre.web/modules/weinre/target/Target.coffee
index 460ece1..70e7099 100644
--- a/weinre.web/modules/weinre/target/Target.coffee
+++ b/weinre.web/modules/weinre/target/Target.coffee
@@ -162,21 +162,9 @@
         Weinre.nodeStore = new NodeStore()
         Weinre.cssStore  = new CSSStore()
 
-        window.addEventListener "error", ((e) ->
-            Target.handleError e
-        ), false
-
         NetworkRequest.installNativeHooks()
 
     #---------------------------------------------------------------------------
-    @handleError: (event) ->
-        filename = event.filename or "[unknown filename]"
-        lineno   = event.lineno   or "[unknown lineno]"
-        message  = event.message  or "[unknown message]"
-
-        console.error "error occurred: #{filename}:#{lineno}: #{message}"
-
-    #---------------------------------------------------------------------------
     cb_webSocketOpened: () ->
         Weinre.WeinreTargetCommands.registerTarget window.location.href, Binding(this, @cb_registerTarget)
 
diff --git a/weinre.web/modules/weinre/target/Timeline.coffee b/weinre.web/modules/weinre/target/Timeline.coffee
index fdf93d5..e774a1e 100644
--- a/weinre.web/modules/weinre/target/Timeline.coffee
+++ b/weinre.web/modules/weinre/target/Timeline.coffee
@@ -150,13 +150,18 @@
     @addRecord_XHRReadyStateChange: (method, url, id, xhr) ->
         return unless Timeline.isRunning()
 
+        try 
+            contentLength = xhr.getResponseHeader("Content-Length")
+            contentLength = parseInt(contentLength)
+            contentType   = xhr.getResponseHeader("Content-Type")
+        catch e
+            contentLength = 0
+            contentType   = "unknown"
+
         record = {}
         record.startTime = Date.now()
         record.category  = name: "loading"
 
-        contentLength = xhr.getResponseHeader("Content-Length")
-        contentLength = parseInt(contentLength)
-
         if xhr.readyState == XMLHttpRequest.OPENED
             record.type = TimelineRecordType.ResourceSendRequest
             record.data =
@@ -169,7 +174,7 @@
             record.data =
                 identifier:            id
                 statusCode:            xhr.status
-                mimeType:              xhr.getResponseHeader("Content-Type")
+                mimeType:              contentType
                 url:                   url
 
             record.data.expectedContentLength = contentLength if !isNaN(contentLength)
@@ -217,6 +222,8 @@
                 @userData.interval = interval
 
             after: (receiver, args, result) ->
+                return if !@userData
+                
                 code = @userData.code
                 return unless typeof(code) is "function"
 
@@ -247,6 +254,8 @@
                 @userData.interval = interval
 
             after: (receiver, args, result) ->
+                return if !@userData
+                
                 code = @userData.code
                 return unless typeof(code) is "function"