diff --git a/thirdparty/firebug-lite/firebug.js b/thirdparty/firebug-lite/firebug.js
index 14eaad2e8..e5eee60d0 100644
--- a/thirdparty/firebug-lite/firebug.js
+++ b/thirdparty/firebug-lite/firebug.js
@@ -1,5 +1,5 @@
 
-if (!window.console || !console.firebug) {
+if (!window.console && !console.firebug) {
 (function()
 {
     window.console = 
diff --git a/thirdparty/firebug-lite/firebugx.js b/thirdparty/firebug-lite/firebugx.js
index 343686250..5f2e521e7 100644
--- a/thirdparty/firebug-lite/firebugx.js
+++ b/thirdparty/firebug-lite/firebugx.js
@@ -1,5 +1,5 @@
 
-if (!window.console || !console.firebug)
+if (!window.console && !console.firebug)
 {
     var names = ["log", "debug", "info", "warn", "error", "assert", "dir", "dirxml",
     "group", "groupEnd", "time", "timeEnd", "count", "trace", "profile", "profileEnd"];