Less JavaScript, More Platform

Modern Browser APIs Front-End Developers Should Actually Use
Courtney Yatteau · TechBash 2026

Modern browsers can handle many interface behaviors that front-end developers still reach for JavaScript to build themselves. This repo contains the demos from the talk, focused on letting the platform own more generic UI behavior while keeping JavaScript focused on application-specific work.

PAUSE before reaching for JavaScript

• P - Pause before reaching for JavaScript
• A - Ask what HTML and CSS can already do
• U - Use the browser platform
• S - Study support and progressive enhancement
• E - Employ JavaScript where it adds real value

The recurring question throughout the talk is:

Do I actually need JavaScript for this?

What the talk covers

• Native <dialog>
• Invoker Commands with command and commandfor
• Popover API
• Native form validation
• View Transitions
• Progressive enhancement and browser-support decisions
• When JavaScript is still the right tool

The City Explorer demos use an ArcGIS map as an example of JavaScript doing specialized work that should stay, while the surrounding UI gets simpler.

Demo files

Each demo is a standalone HTML file with its CSS and JavaScript inlined. There is no npm install or build step.

City Explorer

1. 00-start.html — custom JavaScript modal
2. 01-dialog.html — native <dialog>
3. 02-commands.html — Invoker Commands
4. 03-popover.html — Popover API + category filtering
5. 04-transitions.html — abrupt selected-place state change
6. 05-complete.html — same state change with View Transitions

Forms

• 00-custom.html — custom JavaScript validation
• 01-native.html — native HTML validation

Running the demos

The form demos can be opened directly in a browser.

The City Explorer demos use the ArcGIS Maps SDK for JavaScript and require an ArcGIS API key for the basemap. The public files intentionally contain this placeholder:

YOUR_FRESH_RESTRICTED_ARCGIS_API_KEY

Replace that value in your local copy with your own appropriately restricted API key before running the map demos.

For the smoothest local setup, serve the repo with a small local web server instead of opening the files with file://:

python -m http.server 8080

Then open the demo you want from http://localhost:8080/.

Key takeaway

Platform first. JavaScript on purpose.

Use JavaScript for what it adds, not for what the browser already gives you.

Speaker

Courtney Yatteau
Developer Advocate, Esri
GitHub: @cyatteau