diff --git a/src/main/webapp/resources/applib/js/string-support.js b/src/main/webapp/resources/applib/js/string-support.js
index a1b1530..c0b73ee 100644
--- a/src/main/webapp/resources/applib/js/string-support.js
+++ b/src/main/webapp/resources/applib/js/string-support.js
@@ -134,7 +134,7 @@ class StringSupport {
 		
 		// 유효날짜 확인
 		if (year>="0001" && year<="9999" && month>="01" && month<="12") {
-			febDays = "29";
+			let febDays = "29";
 			if ((parseInt(year,10) % 4) == 0) {
 				if ((parseInt(year,10) % 100) == 0 && (parseInt(year,10) % 400) != 0){
 					febDays = "28";