diff --git a/src/mujs/jserror.c b/src/mujs/jserror.c
index 99a1bbc..6dd3bb1 100644
--- a/src/mujs/jserror.c
+++ b/src/mujs/jserror.c
@@ -61,7 +61,7 @@ static int jsB_ErrorX(js_State *J, js_Object *prototype)
 		js_defproperty(J, -2, "message", JS_DONTENUM);
 	}
 	if (jsB_stacktrace(J, 1))
-		js_defproperty(J, -2, "stackTrace", JS_DONTENUM);
+		js_defproperty(J, -2, "stack", JS_DONTENUM);
 	return 1;
 }
 
@@ -71,7 +71,7 @@ static void js_newerrorx(js_State *J, const char *message, js_Object *prototype)
 	js_pushstring(J, message);
 	js_setproperty(J, -2, "message");
 	if (jsB_stacktrace(J, 0))
-		js_setproperty(J, -2, "stackTrace");
+		js_setproperty(J, -2, "stack");
 }
 
 #define DERROR(name, Name) \
diff --git a/src/mujs/jsstring.c b/src/mujs/jsstring.c
index 4954d75..da12431 100644
--- a/src/mujs/jsstring.c
+++ b/src/mujs/jsstring.c
@@ -288,8 +288,10 @@ static void Sp_slice(js_State *J)
 
 	if (s < e)
 		Sp_substring_imp(J, str, s, e - s);
-	else
+	else if (s > e)
 		Sp_substring_imp(J, str, e, s - e);
+	else
+		js_pushliteral(J, "");
 }
 
 static void Sp_substring(js_State *J)
@@ -304,8 +306,10 @@ static void Sp_substring(js_State *J)
 
 	if (s < e)
 		Sp_substring_imp(J, str, s, e - s);
-	else
+	else if (s > e)
 		Sp_substring_imp(J, str, e, s - e);
+	else
+		js_pushliteral(J, "");
 }
 
 static void Sp_toLowerCase(js_State *J)
diff --git a/src/mujs/regexp.c b/src/mujs/regexp.c
index 952a1d2..26d534f 100644
--- a/src/mujs/regexp.c
+++ b/src/mujs/regexp.c
@@ -147,7 +147,7 @@ static int nextrune(struct cstate *g)
 				g->yychar = '0';
 				return 1;
 			}
-			return 0;
+			return 1;
 		case 'u':
 			if (!g->source[0] || !g->source[1] || !g->source[2] || !g->source[3])
 				die(g, "unterminated escape sequence");
@@ -159,7 +159,7 @@ static int nextrune(struct cstate *g)
 				g->yychar = '0';
 				return 1;
 			}
-			return 0;
+			return 1;
 		case 0:
 			g->yychar = '0';
 			return 1;