adding the validation for manual input on customer create, on frontend

Author: tiagooctp

app/code/Magento/Customer/Block/Widget/Dob.php

@@ -267,6 +267,8 @@ public function getHtmlExtraParams()
         $validators['validate-date'] = [
             'dateFormat' => $this->getDateFormat()
         ];
+        $validators['validate-dob'] = true;
+
         return 'data-validate="' . $this->_escaper->escapeHtml(json_encode($validators)) . '"';
     }
 

app/code/Magento/Customer/view/frontend/templates/widget/dob.phtml

@@ -35,3 +35,11 @@ $fieldCssClass .= $block->isRequired() ? ' required' : '';
         <?php endif; ?>
     </div>
 </div>
+
+<script type="text/x-magento-init">
+    {
+       "*": {
+           "Magento_Customer/js/validation": {}
+       }
+    }
+ </script>

app/code/Magento/Customer/view/frontend/web/js/validation.js

@@ -0,0 +1,19 @@
+require([
+    'jquery',
+    'moment',
+    'jquery/ui',
+    'jquery/validate',
+    'mage/translate',
+], function($, moment) {
+    'use strict';
+    $.validator.addMethod(
+        "validate-dob",
+        function (value) {
+            if (value === '') {
+                return true;
+            }
+            return moment(value).isBefore(moment());
+        },
+        $.mage.__('The Date of Birth should not be greater than today.')
+    );
+});