AJAX to HTMX Migration

I need to...	Guide	Summary
Understand architectural differences before migrating	AJAX vs HTMX Fundamentals	Use AJAX when you need command sequences, modal dialogs, or contrib integration. Use HTMX when you want declarative form interactions, CSS selector targeting, or built-in browser history support.
Find the HTMX equivalent of a specific AJAX command	AJAX Command to HTMX Equivalents	Use this reference when converting existing AJAX commands to HTMX patterns. Find the HTMX equivalent of a specific AJAX command before rewriting.
Migrate a parent select that updates child select options	Dependent Dropdown Migration	Use this when migrating a parent select element that dynamically updates a child select element's options based on the parent's value.
Migrate multiple dependent selects with bookmarkable URL	Cascading Selects with URL Migration	Use this when migrating multiple dependent selects where each selection updates the next dropdown AND the browser URL (bookmarkable state).
Migrate a button that loads content into a container	Button-Triggered Content Load Migration	Use this when migrating a button or link that loads dynamic content into a container on click — "Load More", "Refresh", or content panel patterns.
Migrate a multi-step wizard with browser back/forward	Multi-Step Wizard Migration	Use this when migrating multi-step wizard forms where each step is driven by AJAX navigation. HTMX enables bookmarkable steps with browser back/forward button support.
Migrate field validation on blur without form submission	Real-Time Validation Migration	Use this when migrating field-level validation that runs on blur (focusout) without submitting the form — email availability checks, username validation, format verification.
Migrate Load More or infinite scroll patterns	Infinite Scroll Migration	Use this when migrating "Load More" buttons or infinite scroll patterns that append new content to a list — content listings, search results, and feeds.
Migrate Add Another / dynamic field addition	Dynamic Field Addition Migration	Use this when migrating "Add Another" patterns where clicking a button adds a new form field to the form — multi-value fields and repeating field groups.
Migrate custom JavaScript AJAX event hooks	JavaScript Event Migration	Use this when migrating custom JavaScript that hooks into AJAX events for preprocessing, validation, or post-processing.
Migrate custom AJAX commands (CommandInterface)	Custom AJAX Command Migration	Use this when migrating custom AJAX commands (CommandInterface classes) that perform specialized JavaScript operations. HTMX handles these via trigger headers.
Migrate Drupal behaviors for HTMX swaps	Drupal Behavior Migration	Use this when migrating Drupal behaviors that attach/detach on AJAX swaps. Behaviors work identically with HTMX — the htmx:drupal:load and htmx:drupal:unload events trigger Drupal.attachBehaviors() and Drupal.detachBehaviors()…
Migrate screen reader announcements and focus management	Accessibility Migration	Use this when migrating AnnounceCommand, FocusFirstCommand, and screen reader patterns from AJAX to HTMX. HTMX handles messages automatically but custom announcements need trigger headers.
Decide which AJAX patterns NOT to migrate	When NOT to Migrate	Use AJAX when you need ordered command sequences, the core dialog system, CSS manipulation, jQuery data API, or when contrib modules expect AJAX callbacks.
Use AJAX and HTMX together in the same application	Hybrid AJAX-HTMX Approach	Use both AJAX and HTMX in the same application when you need AJAX for specific features (dialogs, contrib) but want HTMX for new form interactions. They coexist without conflict.
Plan a safe migration rollout	Migration Strategy Best Practices	Use this before starting any AJAX to HTMX migration. Plan priorities, rollout phases, and testing to minimize risk.
Get a step-by-step migration verification checklist	Migration Checklist	Use this checklist for every individual AJAX to HTMX migration to ensure nothing is missed.