diff --git a/core/modules/dependencies.js b/core/modules/dependencies.js
index 6f064dbfd..6d49c8695 100644
--- a/core/modules/dependencies.js
+++ b/core/modules/dependencies.js
@@ -68,7 +68,7 @@ Dependencies.prototype.hasChanged = function(changes,contextTiddlerTitle) {
 		return true;
 	}
 	for(var c in changes) {
-		if(this.tiddlers.hasOwnProperty(c)) {
+		if($tw.utils.hop(this.tiddlers,c)) {
 			return true;
 		}
 	}
diff --git a/core/modules/macros/slider.js b/core/modules/macros/slider.js
index 11d029df7..68323b56f 100644
--- a/core/modules/macros/slider.js
+++ b/core/modules/macros/slider.js
@@ -151,7 +151,7 @@ exports.executeMacro = function() {
 exports.refreshInDom = function(changes) {
 	var needChildrenRefresh = true; // Avoid refreshing the children nodes if we don't need to
 	// If the state tiddler has changed then reset the open state
-	if(this.hasParameter("state") && changes.hasOwnProperty(this.params.state)) {
+	if(this.hasParameter("state") && $tw.utils.hop(changes,this.params.state)) {
 		this.isOpen = this.getOpenState();
 	}
 	// Render the children if the slider is open and we don't have any children yet
diff --git a/core/modules/macros/story.js b/core/modules/macros/story.js
index 55998e853..b1a8d8cc0 100644
--- a/core/modules/macros/story.js
+++ b/core/modules/macros/story.js
@@ -39,7 +39,7 @@ exports.handleEvent = function(event) {
 			template = this.hasParameter("defaultViewTemplate") ? this.params.defaultViewTemplate : "ViewTemplate";
 			storyTiddler = this.wiki.getTiddler(this.params.story);
 			story = {tiddlers: []};
-			if(storyTiddler && storyTiddler.fields.hasOwnProperty("text")) {
+			if(storyTiddler && $tw.utils.hop(storyTiddler.fields,"text")) {
 				story = JSON.parse(storyTiddler.fields.text);
 			}
 			story.tiddlers.unshift({title: event.navigateTo, template: template});
@@ -52,7 +52,7 @@ exports.handleEvent = function(event) {
 			template = this.hasParameter("defaultEditTemplate") ? this.params.defaultEditTemplate : "EditTemplate";
 			storyTiddler = this.wiki.getTiddler(this.params.story);
 			story = {tiddlers: []};
-			if(storyTiddler && storyTiddler.fields.hasOwnProperty("text")) {
+			if(storyTiddler && $tw.utils.hop(storyTiddler.fields,"text")) {
 				story = JSON.parse(storyTiddler.fields.text);
 			}
 			for(t=0; t<story.tiddlers.length; t++) {
@@ -81,14 +81,14 @@ exports.handleEvent = function(event) {
 			storyTiddler = this.wiki.getTiddler(this.params.story);
 			story = {tiddlers: []};
 			storyTiddlerModified = false;
-			if(storyTiddler && storyTiddler.fields.hasOwnProperty("text")) {
+			if(storyTiddler && $tw.utils.hop(storyTiddler.fields,"text")) {
 				story = JSON.parse(storyTiddler.fields.text);
 			}
 			for(t=0; t<story.tiddlers.length; t++) {
 				storyRecord = story.tiddlers[t];
 				if(storyRecord.title === event.tiddlerTitle && storyRecord.template !== template) {
 					tiddler = this.wiki.getTiddler(storyRecord.title);
-					if(tiddler && tiddler.fields.hasOwnProperty("draft.title")) {
+					if(tiddler && $tw.utils.hop(tiddler.fields,"draft.title")) {
 						// Save the draft tiddler as the real tiddler
 						this.wiki.addTiddler(new $tw.Tiddler(tiddler,{title: tiddler.fields["draft.title"],"draft.title": undefined, "draft.of": undefined}));
 						// Remove the draft tiddler
diff --git a/core/modules/treenodes/macro.js b/core/modules/treenodes/macro.js
index e9dfea7d9..1bf95ad49 100644
--- a/core/modules/treenodes/macro.js
+++ b/core/modules/treenodes/macro.js
@@ -117,7 +117,7 @@ Macro.prototype.parseMacroParamString = function(paramString) {
 };
 
 Macro.prototype.hasParameter = function(name) {
-	return this.params.hasOwnProperty(name);
+	return $tw.utils.hop(this.params,name);
 };
 
 Macro.prototype.cloneContent = function() {
diff --git a/core/modules/utils.argparser.js b/core/modules/utils.argparser.js
index e8f320769..487c08c30 100644
--- a/core/modules/utils.argparser.js
+++ b/core/modules/utils.argparser.js
@@ -75,7 +75,7 @@ var ArgParser = function(argString,options) {
 				}
 				if(n.evaluated === true) {
 					n = "{{" + n.string + "}}";
-				} else if (typeof n === "object" && n.hasOwnProperty("string")) {
+				} else if (typeof n === "object" && $tw.utils.hop(n,"string")) {
 					n = n.string;
 				}
 				this.byPos.push({n:n, v:v});
@@ -90,7 +90,7 @@ var ArgParser = function(argString,options) {
 	for(var t=0; t<this.byPos.length; t++) {
 		n = this.byPos[t].n;
 		v = this.byPos[t].v;
-		if(this.byName.hasOwnProperty(n))
+		if($tw.utils.hop(this.byName,n))
 			this.byName[n].push(v);
 		else
 			this.byName[n] = [v];
diff --git a/core/modules/wiki.js b/core/modules/wiki.js
index 8d22c7aee..9d4285c76 100644
--- a/core/modules/wiki.js
+++ b/core/modules/wiki.js
@@ -62,7 +62,7 @@ exports.touchTiddler = function(title,isDeleted) {
 	this.changedTiddlers[title][isDeleted ? "deleted" : "modified"] = true;
 	// Increment the change count
 	this.changeCount = this.changeCount || {};
-	if(this.changeCount.hasOwnProperty(title)) {
+	if($tw.utils.hop(this.changeCount,title)) {
 		this.changeCount[title]++;
 	} else {
 		this.changeCount[title] = 1;
@@ -86,7 +86,7 @@ exports.touchTiddler = function(title,isDeleted) {
 
 exports.getChangeCount = function(title) {
 	this.changeCount = this.changeCount || {};
-	if(this.changeCount.hasOwnProperty(title)) {
+	if($tw.utils.hop(this.changeCount,title)) {
 		return this.changeCount[title];
 	} else {
 		return 0;
@@ -227,7 +227,7 @@ exports.getCacheForTiddler = function(title,cacheName,initializer) {
 // Clear all caches associated with a particular tiddler
 exports.clearCache = function(title) {
 	this.caches = this.caches || {};
-	if(this.caches.hasOwnProperty(title)) {
+	if($tw.utils.hop(this.caches,title)) {
 		delete this.caches[title];
 	}
 };