Drupal AJAX

As of Drupal 11.3, HTMX is available in core and is the recommended approach for new projects. This guide covers the legacy AJAX framework, which remains essential for existing codebases and contributed module patterns.

I need to...	Guide
Understand the AJAX system architecture	Core Concepts
Add AJAX to a form element	Form Element AJAX Configuration
Create dependent fields (category/subcategory)	Dependent Field Patterns
Build a multi-step wizard form	Multi-Step Form Workflows
Validate fields as user types	Live Field Validation
Update, append, or remove DOM content	Content Manipulation Commands
Add CSS classes or invoke jQuery methods	CSS Styling Commands
Open or close modal dialogs	Dialog Commands
Show messages or screen reader alerts	Feedback Commands
Create a custom AJAX command	Custom AJAX Commands
Build a custom AJAX route (non-Form API)	Custom Route Implementation
Handle file uploads via AJAX	File Upload Patterns
Implement autocomplete suggestions	Autocomplete Implementation
Restrict access to AJAX callbacks	Access Control Patterns
Protect AJAX endpoints from CSRF	CSRF Protection
Optimize slow AJAX requests	Performance Optimization
Cache AJAX responses	Response Caching
Make AJAX meet WCAG 2.1 AA	WCAG Compliance Patterns
Announce updates to screen readers	Screen Reader Support
Debug failing AJAX requests	Debugging Techniques
Write automated AJAX tests	Testing AJAX
Integrate React or Vue with Drupal	Frontend Framework Integration
Apply security best practices	Best Practices: Security
Apply performance best practices	Best Practices: Performance
Follow Drupal development standards	Best Practices: Development Standards
Meet accessibility requirements	Best Practices: Accessibility