diff --git a/src/ecmascript/spidermonkey.c b/src/ecmascript/spidermonkey.c
index 01a66aed..ce25a93e 100644
--- a/src/ecmascript/spidermonkey.c
+++ b/src/ecmascript/spidermonkey.c
@@ -539,7 +539,7 @@ spidermonkey_eval_stringback(struct ecmascript_interpreter *interpreter,
 		/* Undefined value. */
 		result = NULL;
 	} else {
-		result = stracpy(jsval_to_string(ctx, r_rval));
+		result = jsval_to_string(ctx, r_rval);
 	}
 	JS::LeaveRealm(ctx, comp);
 
diff --git a/src/ecmascript/spidermonkey/console.c b/src/ecmascript/spidermonkey/console.c
index 060ddd62..6b922355 100644
--- a/src/ecmascript/spidermonkey/console.c
+++ b/src/ecmascript/spidermonkey/console.c
@@ -106,6 +106,7 @@ console_log(JSContext *ctx, unsigned int argc, JS::Value *vp)
 			fprintf(f, "%s\n", key);
 			fclose(f);
 		}
+		mem_free_if(key);
 	}
 
 	args.rval().setBoolean(true);
diff --git a/src/ecmascript/spidermonkey/document.c b/src/ecmascript/spidermonkey/document.c
index 8e9865dc..ad34c39c 100644
--- a/src/ecmascript/spidermonkey/document.c
+++ b/src/ecmascript/spidermonkey/document.c
@@ -292,7 +292,9 @@ document_set_property_cookie(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	if (!vs) {
 		return false;
 	}
-	set_cookie(vs->uri, jsval_to_string(ctx, args[0]));
+	char *text = jsval_to_string(ctx, args[0]);
+	set_cookie(vs->uri, text);
+	mem_free_if(text);
 
 	return true;
 }
@@ -751,7 +753,12 @@ document_set_property_location(JSContext *ctx, unsigned int argc, JS::Value *vp)
 		return false;
 	}
 	doc_view = vs->doc_view;
-	location_goto(doc_view, jsval_to_string(ctx, args[0]));
+	char *url = jsval_to_string(ctx, args[0]);
+
+	if (url) {
+		location_goto(doc_view, url);
+		mem_free(url);
+	}
 
 	return true;
 }
@@ -936,7 +943,7 @@ document_set_property_title(JSContext *ctx, int argc, JS::Value *vp)
 	}
 	doc_view = vs->doc_view;
 	document = doc_view->document;
-	mem_free_set(&document->title, stracpy(jsval_to_string(ctx, args[0])));
+	mem_free_set(&document->title, jsval_to_string(ctx, args[0]));
 	print_screen_status(doc_view->session);
 
 	return true;
@@ -1006,7 +1013,11 @@ document_set_property_url(JSContext *ctx, unsigned int argc, JS::Value *vp)
 		return false;
 	}
 	doc_view = vs->doc_view;
-	location_goto(doc_view, jsval_to_string(ctx, args[0]));
+	char *url = jsval_to_string(ctx, args[0]);
+	if (url) {
+		location_goto(doc_view, url);
+		mem_free(url);
+	}
 
 	return true;
 }
diff --git a/src/ecmascript/spidermonkey/element.c b/src/ecmascript/spidermonkey/element.c
index 81e00e13..e9f7494b 100644
--- a/src/ecmascript/spidermonkey/element.c
+++ b/src/ecmascript/spidermonkey/element.c
@@ -1601,10 +1601,12 @@ element_set_property_className(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	if (!el) {
 		return true;
 	}
+	char *val = jsval_to_string(ctx, args[0]);
 
-	std::string value = jsval_to_string(ctx, args[0]);
+	std::string value = val;
 	el->set_attribute("class", value);
 	interpreter->changed = true;
+	mem_free_if(val);
 
 	return true;
 }
@@ -1642,12 +1644,14 @@ element_set_property_dir(JSContext *ctx, unsigned int argc, JS::Value *vp)
 		return true;
 	}
 
-	std::string value = jsval_to_string(ctx, args[0]);
+	char *val = jsval_to_string(ctx, args[0]);
+	std::string value = val;
 
 	if (value == "ltr" || value == "rtl" || value == "auto") {
 		el->set_attribute("dir", value);
 		interpreter->changed = true;
 	}
+	mem_free_if(val);
 
 	return true;
 }
@@ -1686,10 +1690,13 @@ element_set_property_id(JSContext *ctx, unsigned int argc, JS::Value *vp)
 		return true;
 	}
 
-	std::string value = jsval_to_string(ctx, args[0]);
+	char *val = jsval_to_string(ctx, args[0]);
+	std::string value = val;
 	el->set_attribute("id", value);
 	interpreter->changed = true;
 
+	mem_free_if(val);
+
 	return true;
 }
 
@@ -1734,8 +1741,10 @@ element_set_property_innerHtml(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	}
 
 	std::string text = "<root>";
-	text += jsval_to_string(ctx, args[0]);
+	char *vv = jsval_to_string(ctx, args[0]);
+	text += vv;
 	text += "</root>";
+	mem_free_if(vv);
 
 	xmlDoc* doc = htmlReadDoc((xmlChar*)text.c_str(), NULL, NULL, HTML_PARSE_RECOVER | HTML_PARSE_NOERROR | HTML_PARSE_NOWARNING);
 	// Encapsulate raw libxml document in a libxml++ wrapper
@@ -1798,6 +1807,7 @@ element_set_property_innerText(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	char *text = jsval_to_string(ctx, args[0]);
 	el->add_child_text(text);
 	interpreter->changed = true;
+	mem_free_if(text);
 
 	return true;
 }
@@ -1835,10 +1845,13 @@ element_set_property_lang(JSContext *ctx, unsigned int argc, JS::Value *vp)
 		return true;
 	}
 
-	std::string value = jsval_to_string(ctx, args[0]);
+	char *val = jsval_to_string(ctx, args[0]);
+	std::string value = val;
 	el->set_attribute("lang", value);
 	interpreter->changed = true;
 
+	mem_free_if(val);
+
 	return true;
 }
 
@@ -1938,10 +1951,13 @@ element_set_property_title(JSContext *ctx, unsigned int argc, JS::Value *vp)
 		return true;
 	}
 
-	std::string value = jsval_to_string(ctx, args[0]);
+	char *val = jsval_to_string(ctx, args[0]);
+	std::string value = val;
 	el->set_attribute("title", value);
 	interpreter->changed = true;
 
+	mem_free_if(val);
+
 	return true;
 }
 
@@ -2113,11 +2129,14 @@ element_getAttributeNode(JSContext *ctx, unsigned int argc, JS::Value *rval)
 		args.rval().setUndefined();
 		return true;
 	}
-	std::string v = jsval_to_string(ctx, args[0]);
+	char *vv = jsval_to_string(ctx, args[0]);
+	std::string v = vv;
 	xmlpp::Attribute *attr = el->get_attribute(v);
 	JSObject *obj = getAttr(ctx, attr);
 	args.rval().setObject(*obj);
 
+	mem_free_if(vv);
+
 	return true;
 }
 
@@ -2148,10 +2167,13 @@ element_hasAttribute(JSContext *ctx, unsigned int argc, JS::Value *rval)
 		args.rval().setBoolean(false);
 		return true;
 	}
-	std::string v = jsval_to_string(ctx, args[0]);
+	char *vv = jsval_to_string(ctx, args[0]);
+	std::string v = vv;
 	xmlpp::Attribute *attr = el->get_attribute(v);
 	args.rval().setBoolean((bool)attr);
 
+	mem_free_if(vv);
+
 	return true;
 }
 
@@ -2406,10 +2428,14 @@ element_setAttribute(JSContext *ctx, unsigned int argc, JS::Value *rval)
 	}
 
 	if (args[0].isString() && args[1].isString()) {
-		std::string attr = jsval_to_string(ctx, args[0]);
-		std::string value = jsval_to_string(ctx, args[1]);
+		char *attr_c = jsval_to_string(ctx, args[0]);
+		std::string attr = attr_c;
+		char *value_c = jsval_to_string(ctx, args[1]);
+		std::string value = value_c;
 		el->set_attribute(attr, value);
 		interpreter->changed = true;
+		mem_free_if(attr_c);
+		mem_free_if(value_c);
 	}
 
 	return true;
@@ -2548,6 +2574,8 @@ htmlCollection_namedItem(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	bool ret = htmlCollection_namedItem2(ctx, hobj, str, &rval);
 	args.rval().set(rval);
 
+	mem_free_if(str);
+
 	return ret;
 }
 
@@ -2674,10 +2702,15 @@ htmlCollection_get_property(JSContext *ctx, JS::HandleObject hobj, JS::HandleId
 		JS_IdToValue(ctx, id, &r_idval);
 		char *string = jsval_to_string(ctx, r_idval);
 
-		std::string test = string;
+		if (string) {
+			std::string test = string;
 
-		if (test != "item" && test != "namedItem") {
-			return htmlCollection_namedItem2(ctx, hobj, string, hvp);
+			if (test != "item" && test != "namedItem") {
+				bool ret = htmlCollection_namedItem2(ctx, hobj, string, hvp);
+				mem_free(string);
+				return ret;
+			}
+			mem_free(string);
 		}
 	}
 
@@ -3016,6 +3049,8 @@ attributes_getNamedItem(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	bool ret = attributes_namedItem2(ctx, hobj, str, &rval);
 	args.rval().set(rval);
 
+	mem_free_if(str);
+
 	return ret;
 }
 
diff --git a/src/ecmascript/spidermonkey/form.c b/src/ecmascript/spidermonkey/form.c
index e09fbc68..862c44f2 100644
--- a/src/ecmascript/spidermonkey/form.c
+++ b/src/ecmascript/spidermonkey/form.c
@@ -366,7 +366,7 @@ input_set_property_alt(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	assert(fc);
 	assert(fc->form && fs);
 
-	mem_free_set(&fc->alt, stracpy(jsval_to_string(ctx, args[0])));
+	mem_free_set(&fc->alt, jsval_to_string(ctx, args[0]));
 
 	return true;
 }
@@ -780,7 +780,7 @@ input_set_property_name(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	assert(fc);
 	assert(fc->form && fs);
 
-	mem_free_set(&fc->name, stracpy(jsval_to_string(ctx, args[0])));
+	mem_free_set(&fc->name, jsval_to_string(ctx, args[0]));
 
 	return true;
 }
@@ -1136,7 +1136,7 @@ input_set_property_src(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	if (linknum >= 0) link = &document->links[linknum];
 
 	if (link) {
-		mem_free_set(&link->where_img, stracpy(jsval_to_string(ctx, args[0])));
+		mem_free_set(&link->where_img, jsval_to_string(ctx, args[0]));
 	}
 
 	return true;
@@ -1326,7 +1326,7 @@ input_set_property_value(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	assert(fc->form && fs);
 
 	if (fc->type != FC_FILE) {
-		mem_free_set(&fs->value, stracpy(jsval_to_string(ctx, args[0])));
+		mem_free_set(&fs->value, jsval_to_string(ctx, args[0]));
 		if (fc->type == FC_TEXT || fc->type == FC_PASSWORD)
 			fs->state = strlen(fs->value);
 	}
@@ -1812,12 +1812,16 @@ form_elements_get_property(JSContext *ctx, JS::HandleObject hobj, JS::HandleId h
 		JS_IdToValue(ctx, id, &r_idval);
 		char *string = jsval_to_string(ctx, r_idval);
 
-		std::string test = string;
-		if (test == "item" || test == "namedItem") {
-			return true;
-		}
+		if (string) {
+			std::string test = string;
+			if (test == "item" || test == "namedItem") {
+				mem_free(string);
+				return true;
+			}
 
-		form_elements_namedItem2(ctx, hobj, string, hvp);
+			form_elements_namedItem2(ctx, hobj, string, hvp);
+			mem_free(string);
+		}
 		return true;
 	}
 
@@ -1974,12 +1978,11 @@ form_elements_namedItem(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	JS::RootedObject hobj(ctx, &args.thisv().toObject());
 	JS::RootedValue rval(ctx, val);
 
-
-//	JS::Value *argv = JS_ARGV(ctx, rval);
 	char *string = jsval_to_string(ctx, args[0]);
 	bool ret = form_elements_namedItem2(ctx, hobj, string, &rval);
 	args.rval().set(rval);
-//	JS_SET_RVAL(ctx, rval, val);
+	mem_free_if(string);
+
 	return ret;
 }
 
@@ -2247,7 +2250,7 @@ form_set_property_action(JSContext *ctx, unsigned int argc, JS::Value *vp)
 
 	assert(form);
 
-	string = stracpy(jsval_to_string(ctx, args[0]));
+	string = jsval_to_string(ctx, args[0]);
 	if (form->action) {
 		ecmascript_set_action(&form->action, string);
 	} else {
@@ -2386,6 +2389,9 @@ form_set_property_encoding(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	assert(form);
 
 	string = jsval_to_string(ctx, args[0]);
+	if (!string) {
+		return true;
+	}
 	if (!c_strcasecmp(string, "application/x-www-form-urlencoded")) {
 		form->method = form->method == FORM_METHOD_GET ? FORM_METHOD_GET
 		                                               : FORM_METHOD_POST;
@@ -2394,6 +2400,7 @@ form_set_property_encoding(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	} else if (!c_strcasecmp(string, "text/plain")) {
 		form->method = FORM_METHOD_POST_TEXT_PLAIN;
 	}
+	mem_free(string);
 
 	return true;
 }
@@ -2535,11 +2542,15 @@ form_set_property_method(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	assert(form);
 
 	string = jsval_to_string(ctx, args[0]);
+	if (!string) {
+		return true;
+	}
 	if (!c_strcasecmp(string, "GET")) {
 		form->method = FORM_METHOD_GET;
 	} else if (!c_strcasecmp(string, "POST")) {
 		form->method = FORM_METHOD_POST;
 	}
+	mem_free(string);
 
 	return true;
 }
@@ -2625,7 +2636,7 @@ form_set_property_name(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	form = find_form_by_form_view(doc_view->document, fv);
 
 	assert(form);
-	mem_free_set(&form->name, stracpy(jsval_to_string(ctx, args[0])));
+	mem_free_set(&form->name, jsval_to_string(ctx, args[0]));
 
 	return true;
 }
@@ -2709,7 +2720,7 @@ form_set_property_target(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	form = find_form_by_form_view(doc_view->document, fv);
 
 	assert(form);
-	mem_free_set(&form->target, stracpy(jsval_to_string(ctx, args[0])));
+	mem_free_set(&form->target, jsval_to_string(ctx, args[0]));
 
 	return true;
 }
@@ -3144,6 +3155,8 @@ forms_namedItem(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	find_form_by_name(ctx, doc_view, string, &rval);
 	args.rval().set(rval.get());
 
+	mem_free_if(string);
+
 	return true;
 }
 
diff --git a/src/ecmascript/spidermonkey/localstorage.c b/src/ecmascript/spidermonkey/localstorage.c
index 1793d68f..ed0969b7 100644
--- a/src/ecmascript/spidermonkey/localstorage.c
+++ b/src/ecmascript/spidermonkey/localstorage.c
@@ -156,8 +156,6 @@ localstorage_getitem(JSContext *ctx, unsigned int argc, JS::Value *vp)
 
 	struct ecmascript_interpreter *interpreter = JS::GetRealmPrivate(comp);
 	JS::CallArgs args = CallArgsFromVp(argc, vp);
-        unsigned char *key = jsval_to_string(ctx, args[0]);
-	//DBG("localstorage get by key: %s\n", args);
 
 	if (argc != 1)
 	{
@@ -165,18 +163,19 @@ localstorage_getitem(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	       return(true);
 	}
 
-	unsigned char *val;
+	unsigned char *key = jsval_to_string(ctx, args[0]);
+	if (key) {
+		unsigned char *val = readFromStorage(key);
 
-        val = readFromStorage(key);
+		//DBG("%s %s\n", key, val);
 
-	//DBG("%s %s\n", key, val);
+		args.rval().setString(JS_NewStringCopyZ(ctx, val));
 
-	args.rval().setString(JS_NewStringCopyZ(ctx, val));
-
-	mem_free(val);
-
-	return(true);
+		mem_free(val);
+		mem_free(key);
+	}
 
+	return true;
 }
 
 /* @localstorage_funcs{"setItem"} */
diff --git a/src/ecmascript/spidermonkey/location.c b/src/ecmascript/spidermonkey/location.c
index aa9ede4b..baff61e9 100644
--- a/src/ecmascript/spidermonkey/location.c
+++ b/src/ecmascript/spidermonkey/location.c
@@ -743,7 +743,12 @@ location_set_property_href(JSContext *ctx, unsigned int argc, JS::Value *vp)
 		return false;
 	}
 	doc_view = vs->doc_view;
-	location_goto(doc_view, jsval_to_string(ctx, args[0]));
+	char *url = jsval_to_string(ctx, args[0]);
+
+	if (url) {
+		location_goto(doc_view, url);
+		mem_free(url);
+	}
 
 	return true;
 }
diff --git a/src/ecmascript/spidermonkey/window.c b/src/ecmascript/spidermonkey/window.c
index 51b85514..45ad639c 100644
--- a/src/ecmascript/spidermonkey/window.c
+++ b/src/ecmascript/spidermonkey/window.c
@@ -244,11 +244,11 @@ window_alert(JSContext *ctx, unsigned int argc, JS::Value *rval)
 
 	string = jsval_to_string(ctx, args[0]);
 
-	if (!*string)
+	if (!string)
 		return true;
 
 	info_box(vs->doc_view->session->tab->term, MSGBOX_FREE_TEXT,
-		N_("JavaScript Alert"), ALIGN_CENTER, stracpy(string));
+		N_("JavaScript Alert"), ALIGN_CENTER, string);
 
 	args.rval().setUndefined();
 	return true;
@@ -308,7 +308,10 @@ window_open(JSContext *ctx, unsigned int argc, JS::Value *rval)
 		}
 	}
 
-	url = stracpy(jsval_to_string(ctx, args[0]));
+	url = jsval_to_string(ctx, args[0]);
+	if (!url) {
+		return true;
+	}
 	trim_chars(url, ' ', 0);
 	url2 = join_urls(doc_view->document->uri, url);
 	mem_free(url);
@@ -316,7 +319,7 @@ window_open(JSContext *ctx, unsigned int argc, JS::Value *rval)
 		return true;
 	}
 	if (argc > 1) {
-		frame = stracpy(jsval_to_string(ctx, args[1]));
+		frame = jsval_to_string(ctx, args[1]);
 		if (!frame) {
 			mem_free(url2);
 			return true;
@@ -406,11 +409,6 @@ window_setTimeout(JSContext *ctx, unsigned int argc, JS::Value *rval)
 	if (args[0].isString()) {
 		code = jsval_to_string(ctx, args[0]);
 
-		if (!*code) {
-			return true;
-		}
-		code = stracpy(code);
-
 		if (!code) {
 			return true;
 		}
@@ -530,7 +528,7 @@ window_set_property_status(JSContext *ctx, unsigned int argc, JS::Value *vp)
 		return true;
 	}
 
-	mem_free_set(&vs->doc_view->session->status.window_status, stracpy(jsval_to_string(ctx, args[0])));
+	mem_free_set(&vs->doc_view->session->status.window_status, jsval_to_string(ctx, args[0]));
 	print_screen_status(vs->doc_view->session);
 
 	return true;