Version 2.1 - simplified locking

leopard.user.js

@@ -1,13 +1,12 @@
 // ==UserScript==
 // @name s/keyboard/leopard/g
-// @version 2.0
+// @version 2.1
 // @description Replaces the word "keyboard" with "leopard".
 // @match *://*/*
 // @updateURL http://userscripts.org/scripts/source/128626.meta.js
 // @downloadURL https://userscripts.org/scripts/source/128626.user.js
 // ==/UserScript==
 
-
 function leopardize(str) {
   return str.replace(/keyboard/g,"leopard")
     .replace(/Keyboard/g,"Leopard")
@@ -16,8 +15,14 @@ function leopardize(str) {
     .replace(/K[Ee][Yy][Bb][Oo][Aa][Rr][Dd]/g,"Leopard")
 }
 
+var replacingContent = false
+
 function replaceTextContent(node) {
+  //flag that content is being replaced so the event it generates
+  //won't trigger another replacement
+  replacingContent = true
   node.textContent = leopardize(node.textContent)
+  replacingContent = false
 }
 
 function changeTextNodes(node) {
@@ -35,25 +40,19 @@ function changeTextNodes(node) {
   }
 }
 
-var replacement_running
-
-function lock_safe(f,param) {
-  if(!replacement_running){
-    replacement_running = true
-    f(param)
-    replacement_running = false
-  }
-}
-
 function insertion_listener(event) {
-  lock_safe(changeTextNodes,event.target)
+  //change any new text nodes in a node that is added to the body
+  changeTextNodes(event.target)
 }
 
 function cdm_listener(event) {
-  lock_safe(replaceTextContent,event.target)
+  //avoid infinite loop by ignoring events triggered by replacement
+  if(!replacingContent){
+    replaceTextContent(event.target)
+  }
 }
 
 changeTextNodes(document.body)
+document.title = leopardize(document.title)
 document.body.addEventListener ("DOMNodeInserted", insertion_listener, false)
 document.body.addEventListener ("DOMCharacterDataModified", cdm_listener, false)
-document.title = leopardize(document.title)