Issue #1551616 by Jumoke: Added Does this work on Tab out?.

clientside_validation.admin.inc

@@ -69,6 +69,18 @@ function clientside_validation_admin_settings() {
     '#default_value' => variable_get('clientside_validation_validate_onblur', 1),
   );
 
+  $form['clientside_validation_validate_options']['clientside_validation_validate_onblur_always'] = array(
+    '#type' => 'radios',
+    '#options' => array(
+      '1' => t('Yes'),
+      '0' => t('No'),
+    ),
+    '#title' => t('Always validate fields on blur'),
+    '#description' => t('Validate elements (except checkboxes/radio buttons) on blur, <strong>even nothing is entered before or if the fields hasn\'t been marked as invalid before.</strong>'),
+    '#default_value' => variable_get('clientside_validation_validate_onblur_always', 0),
+    '#states' => array('visible' => array(':input[name=\'clientside_validation_validate_onblur\']' => array('value' => 1))),
+  );
+
   $form['clientside_validation_validate_options']['clientside_validation_validate_onkeyup'] = array(
     '#type' => 'radios',
     '#options' => array(

clientside_validation.js

@@ -332,6 +332,13 @@
         if (!Boolean(parseInt(self.data.general.validateOnBlur))) {
           validate_options.onfocusout = false;
         }
+        if (Boolean(parseInt(self.data.general.validateOnBlurAlways))) {
+          validate_options.onfocusout = function(element) {
+            if ( !this.checkable(element) ) {
+              this.element(element);
+            }
+          }
+        }
         if (!Boolean(parseInt(self.data.general.validateOnKeyUp))) {
           validate_options.onkeyup = false;
         }

clientside_validation.module

@@ -300,6 +300,7 @@ function _clientside_validation_add_general_settings(&$settings, $form_id) {
     "scrollSpeed" => (int)variable_get('clientside_validation_scroll_speed', 1000),
     "disableHtml5Validation" => variable_get('clientside_validation_disable_html5', 1),
     "validateOnBlur" => variable_get('clientside_validation_validate_onblur', 1),
+    "validateOnBlurAlways" => (int)(variable_get('clientside_validation_validate_onblur_always', 0) && variable_get('clientside_validation_validate_onblur', 1)),
     "validateOnKeyUp" => variable_get('clientside_validation_validate_onkeyup', 1),
     "validateOnSubmit" => variable_get('clientside_validation_validate_onsubmit', 1),
   );