If macOS asks whether you want to open an app downloaded from the internet, click Open. It asks only the first time.
Every release of JSpark is signed and notarized. If it still does not open, see JSpark will not open.
What you see first
JSpark opens with one tab and a short Snippet in it. A moment later it runs by itself, because Run as you type is on. There is no account to make and nothing to set up.
// Press Run, then walk through it with the timeline.
1⌄// Press Run, then walk through it with the timeline.
2⌄// The order things happen in is not the order they are written in.
3⌄
4⌄// Everything here runs as real Node, with the same access to your files,
5⌄// your network and your programs that you have.
Done in 1ms·code changed since·Runs as you typeJSpark
The console prints 1, 2, then 3: the line after await runs after the code below it.
This Snippet shows that code does not always run in the order it is written. It is an ordinary Snippet: change it and see what happens, or close it. Your first Run goes on from here.
The Home screen
Close the tab with ⌘W or Ctrl+W. With no tab open, JSpark shows the Home screen. Pick a Starter to open it in a new tab.
JSpark
What are you trying out?
Node.jsPlain JavaScript or TypeScript on Node.js: read files, call APIs, run scripts. Console output only, no browser.Web PageHTML, CSS and JavaScript that run in the browser. No server: just the page, live beside the code.ReactThe library for web and native user interfaces. Build a UI out of components and hooks, with JSX compiled for you.Web Page + ServerJSpark+A fullstack starter: a web page and its own Node.js server. The page calls the server with fetch("/api/…"), and each side has its own console.React + ServerJSpark+Fullstack React: a React app and its own Node.js server. Components call the server with fetch("/api/…"), and each side has its own console.VueThe progressive JavaScript framework. Approachable, reactive components built on standard HTML, CSS and JavaScript.SvelteA UI framework with a compiler: concise components in HTML, CSS and JavaScript that do minimal work in the browser.three.jsThe JavaScript 3D library. Build a WebGL scene with a camera, lights and meshes, and watch it render on a canvas.jQueryFast, small and feature-rich. DOM traversal, events, animation and Ajax, all through one easy-to-use $ API.D3The library for bespoke data visualization. Bind data to SVG, then shape it with scales, axes and transitions.PreactA fast 3 kB alternative to React with the same modern API. Components, hooks and JSX, at a fraction of the size.SolidDeclarative UI without a Virtual DOM. Signals update only the parts of the page that depend on them, nothing more.LitSimple, fast web components: reactive properties and declarative templates in about 5 kB, usable anywhere HTML is.Alpine.jsA rugged, minimal tool for composing behaviour right in your markup. Think of it like jQuery for the modern web.Web ComponentsCustom elements with no library: a class, a shadow root and customElements.define. The browser's own way to make a new tag.CanvasDraw graphics with JavaScript on an HTML canvas: shapes, animation, game graphics, pixel effects and live visuals.
The Home screen lists every Starter, from Node.js to Canvas.
The next time you open JSpark, it shows the tabs you left open. See Where your work goes.
The pictures show JSpark on a Mac. On Windows, the window looks a little different and uses Ctrl for ⌘, but everything works the same way.
May this site use Google Analytics? It sets cookies to count visits and see which pages are read. Nothing is loaded from Google unless you allow it. More in Privacy.