diff --git a/conservancy/static/js/conservancy.js b/conservancy/static/js/conservancy.js
index dca9848b..92db96df 100644
--- a/conservancy/static/js/conservancy.js
+++ b/conservancy/static/js/conservancy.js
@@ -5,6 +5,8 @@
 **  Find a copy of GPL at https://sfconservancy.org/GPLv3
 */
 
+"use strict";
+
 function qs (selector) {
   return document.querySelector(selector);
 }
diff --git a/conservancy/static/js/supporter-page.js b/conservancy/static/js/supporter-page.js
index 76dc07d6..dea7126d 100644
--- a/conservancy/static/js/supporter-page.js
+++ b/conservancy/static/js/supporter-page.js
@@ -5,6 +5,8 @@
 **  Find a copy of GPL at https://sfconservancy.org/GPLv3
 */
 
+"use strict";
+
 var NEW_AMOUNT_EVENT = 'conservancy:newamount';
 
 var flipClass = function(elem, byeClass, hiClass) {