fix missing JS

Author: schanzer

lib/bootstraplesson.js

@@ -1,6 +1,12 @@
 /*******************************************
  * IDENTIFY OLD VERSIONS
  *******************************************/
+  function UrlExists(url) {
+      var http = new XMLHttpRequest();
+      http.open('HEAD', url, false); // TODO: change this to 'true' and use a promise to render the out of date banner
+      http.send();
+      return (http.status !== 404)
+  }
 
  function isNewest() {
   try{
@@ -13,7 +19,7 @@
       : release.replace(/\/fall\d{4}/, "/spring" + (url_year+1));
 
     // If that version exists, throw up a warning
-    if(UrlExists(release)){
+    if(UrlExists(next_release)){
       var outOfDate = document.createElement('div');
       outOfDate.setAttribute('id', 'outOfDate');
       outOfDate.innerHTML = 'These materials are OUT OF DATE! To get the latest version'