diff --git a/scripts/factorial.js b/scripts/factorial.js
index 26d2a49..46248e1 100644
--- a/scripts/factorial.js
+++ b/scripts/factorial.js
@@ -1,8 +1,11 @@
+//Added a comment - added more detail
 function factorial(n) {
 	n = parseInt(n);
 	var result = 1;
-	for(i = 1; i <= n; i++) {
-		result = result * i;
+	if (n >= 0) {
+		for (i = 1; i <= n; i++) {
+			result = result * i;
+		}
 	}
 	return result;
 }
\ No newline at end of file