AJAX validation in Struts 2 is performed by jsonValidation interceptor. It is not found in the default stack so we need to define it explicitly. It doesn’t perform any validation itself that is why it must be used with validation interceptor. It is found in the jsonValidationWorkflowStack, that includes jsonValidation, validation and workflow interceptors and basicstack.
To use the AJAX validation, you need to add dojo plugin in your project.
Let’s create an example registration form.