From a999ac1ac30bd7ec9db152027fc480ea34652b5d Mon Sep 17 00:00:00 2001
From: Jon Hester <jon.d.hester@gmail.com>
Date: Thu, 5 Mar 2015 13:48:28 +0000
Subject: [PATCH] warn if IE8 is in compatibility mode

---
 src/browser/ui/React.js | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/browser/ui/React.js b/src/browser/ui/React.js
index b5520a15f7..6c25411f6b 100644
--- a/src/browser/ui/React.js
+++ b/src/browser/ui/React.js
@@ -113,6 +113,16 @@ if (__DEV__) {
       }
     }
 
+    // If we're in IE8, check to see if we are in combatibility mode and provide
+    // information on preventing compatibility mode
+    if (document.documentMode && document.documentMode < 8) {
+      console.debug(
+        'Internet Explorer is running in compatibility mode, please add the following ' +
+        'tag to your HTML to prevent this from happening: ' +
+        '<meta http-equiv="X-UA-Compatible" content="IE=edge" />'
+      );
+    }
+
     var expectedFeatures = [
       // shims
       Array.isArray,