diff --git a/docs/assets/js/src/customizer.js b/docs/assets/js/src/customizer.js
index 7fd6216e62..722a039557 100644
--- a/docs/assets/js/src/customizer.js
+++ b/docs/assets/js/src/customizer.js
@@ -417,7 +417,7 @@ window.onload = function () { // wait for load in a dumb way because B-0
     var dependencies = this.getAttribute('data-dependencies')
     if (!dependencies) return
     dependencies = dependencies.split(',')
-    for (var i = 0; i < dependencies.length; i++) {
+    for (var i = 0, len = dependencies.length; i < len; i++) {
       var $dependency = $('[value="' + dependencies[i] + '"]')
       $dependency && $dependency.prop('checked', true)
     }
@@ -428,7 +428,7 @@ window.onload = function () { // wait for load in a dumb way because B-0
     var dependents = this.getAttribute('data-dependents')
     if (!dependents) return
     dependents = dependents.split(',')
-    for (var i = 0; i < dependents.length; i++) {
+    for (var i = 0, len = dependents.length; i < len; i++) {
       var $dependent = $('[value="' + dependents[i] + '"]')
       $dependent && $dependent.prop('checked', false)
     }
diff --git a/js/tests/index.html b/js/tests/index.html
index 3234dc7a8a..d883fa50e6 100644
--- a/js/tests/index.html
+++ b/js/tests/index.html
@@ -42,7 +42,7 @@
           'delegate',
           'undelegate'
         ]
-        for (var i = 0; i < eventAliases.length; i++) {
+        for (var i = 0, len = eventAliases.length; i < len; i++) {
           var eventAlias = eventAliases[i]
           $.fn[eventAlias] = function () {
             throw new Error('Using the ".' + eventAlias + '()" method is not allowed, so that Bootstrap can be compatible with custom jQuery builds which exclude the "event aliases" module that defines said method. See https://github.com/twbs/bootstrap/blob/master/CONTRIBUTING.md#js')
@@ -125,7 +125,7 @@
           'test',
           'throws'
         ];
-        for (var i = 0; i < methodNames.length; i++) {
+        for (var i = 0, len = methodNames.length; i < len; i++) {
           var methodName = methodNames[i];
           window[methodName] = undefined;
         }