Pop-up message does not show up on the second instant

I have a script for a DDL on exit below. If the value of an item starts with 135, a message show up.

I have the DDL in a repeating instant. Script work for the first instant but not for the second!

What I am doing wrong? CC is the Drpo down list.

Thanks

var strNewtext = form1.Page1.ALL.Item_Sub.All_A.details.detail.CC.rawValue.toString();

if (strNewtext.length>3){

if(strNewtext.substring(0,3)=="135")

xfa.host.messageBox("This is……","CAPITAL ACCOUNT",3);