Update with fix by @kmatt from panicsteve#59.

Author: vaguerant

Source/content_script.js

@@ -6,10 +6,10 @@ function walk(node)
 	// http://is.gd/mwZp7E
 
 	var child, next;
-	
-	if (node.tagName.toLowerCase() == 'input' || node.tagName.toLowerCase() == 'textarea'
-	    || node.classList.indexOf('ace_editor') > -1) {
-		return;
+
+	if (node.nodeName.toLowerCase() == 'input' || node.nodeName.toLowerCase() == 'textarea'
+	    || (node.classList && node.classList.contains('ace_editor'))) {
+		 return;
 	}
 
 	switch ( node.nodeType )  

Source/manifest.json

@@ -1,9 +1,9 @@
 {
 	"manifest_version": 2,
 	"name": "Metameater",
-	"version": "1.0.2",
+	"version": "1.0.3",
 	"description": "Replaces the prefix 'meta' with 'meat'.",
-	"developer": { "name": "Vague Rant" },
+	"author": { "name": "Vague Rant" },
 	"icons": {  "48": "icon48.png",
 				"128": "icon128.png" },
 	"content_scripts":