[Skip to content](#main-content) [![Jx Suite](/favicon.svg) Suite](/)Search⌘KESC Jump to [Install Jx Studio](/docs/start/install)[Build your first project](/docs/start/first-project)[Document format](/docs/framework/concepts/documents)[Formula catalog](/docs/framework/reference/formulas) ↵ select↑↓ navigateesc close [Studio](/studio)[Framework](/framework)[Templates](/templates)[Compare](/compare)[Docs](/docs/start/first-project)[GitHub](https://github.com/jxsuite/jx)[Download](/download) ✕ [Studio](/studio)[Framework](/framework)[Templates](/templates)[Compare](/compare)[Docs](/docs/start/first-project)[GitHub](https://github.com/jxsuite/jx) Color scheme [Download](/download) ☰ Docs menu Start here[Overview](/docs/start/)Get started[Install Jx Studio](/docs/start/install/)[Your first project](/docs/start/first-project/)[A tour of Jx Studio](/docs/start/studio-tour/)Tutorials[Tutorial: interactive component](/docs/start/first-component/)[Tutorial: blog with 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tab](/docs/studio/design/properties/)[Style inspector](/docs/studio/design/style-inspector/)[Breakpoints](/docs/studio/design/breakpoints/)[States and selectors](/docs/studio/design/states-and-selectors/)[Design tokens](/docs/studio/design/tokens/)[Project Styles](/docs/studio/design/stylebook/)[Working with components](/docs/studio/design/components/)[Repeaters](/docs/studio/design/repeaters/)Logic[Overview](/docs/studio/logic/)[Formulas and expressions](/docs/studio/logic/formulas/)[Formula workspace](/docs/studio/logic/formula-workspace/)[Statements](/docs/studio/logic/statements/)[Logic tab](/docs/studio/logic/events/)[Data](/docs/studio/logic/data/)[Data sources](/docs/studio/logic/data-sources/)[Code editing](/docs/studio/logic/code/)Databases[Overview](/docs/studio/data/)[Connections](/docs/studio/data/connections/)[Data tables](/docs/studio/data/tables/)[Data grid](/docs/studio/data/grid/)[Auth and secrets](/docs/studio/data/auth-and-secrets/)AI assistant[Overview](/docs/studio/ai/)[The AI assistant](/docs/studio/ai/chat/)[Document assistant](/docs/studio/ai/document-assistant/)Publish[Overview](/docs/studio/publish/)[Source control](/docs/studio/publish/source-control/)[GitHub](/docs/studio/publish/github/)[Cloudflare Pages](/docs/studio/publish/cloudflare/)[Other hosts](/docs/studio/publish/other-hosts/)[Redirects](/docs/studio/publish/redirects/)[Real-time collaboration](/docs/studio/publish/collaboration/)Framework[Overview](/docs/framework/)Concepts[Documents](/docs/framework/concepts/documents/)[Elements](/docs/framework/concepts/elements/)[Components](/docs/framework/concepts/components/)[Props and scope](/docs/framework/concepts/props-and-scope/)[State](/docs/framework/concepts/state/)[Reactivity](/docs/framework/concepts/reactivity/)[References](/docs/framework/concepts/references/)[Expressions](/docs/framework/concepts/expressions/)[Statements](/docs/framework/concepts/statements/)[Functions and sidecars](/docs/framework/concepts/functions/)[Styling](/docs/framework/concepts/styling/)[Color schemes](/docs/framework/concepts/color-schemes/)[Popovers and overlays](/docs/framework/concepts/overlays/)[Accessibility](/docs/framework/concepts/accessibility/)[Lists and iteration](/docs/framework/concepts/lists/)[Data prototypes](/docs/framework/concepts/data-prototypes/)[Timing](/docs/framework/concepts/timing/)[Dynamic switching](/docs/framework/concepts/switching/)[Security](/docs/framework/concepts/security/)Site architecture[Overview](/docs/framework/site/)[project.json](/docs/framework/site/project-json/)[Routing](/docs/framework/site/routing/)[Layouts](/docs/framework/site/layouts/)[Content collections](/docs/framework/site/content-collections/)[Jx Markdown](/docs/framework/site/jx-markdown/)[Obsidian vault as content](/docs/framework/site/obsidian-vault/)[Relationships](/docs/framework/site/relationships/)[SEO and metadata](/docs/framework/site/seo/)[Locales and languages](/docs/framework/site/i18n/)[Images](/docs/framework/site/images/)[Redirects](/docs/framework/site/redirects/)[Feeds](/docs/framework/site/feeds/)[Site search](/docs/framework/site/search/)[Build output and adapters](/docs/framework/site/deployment/)How compilation works[Overview](/docs/framework/build/)[The dev server](/docs/framework/build/dev-server/)[CLI commands](/docs/framework/build/cli/)Working with agents[Overview](/docs/framework/agents/)[Authoring rules for agents](/docs/framework/agents/authoring-rules/)[Machine-readable docs](/docs/framework/agents/machine-readable/)Reference[Overview](/docs/framework/reference/)[Formula catalog](/docs/framework/reference/formulas/)[Operator reference](/docs/framework/reference/operators/)Extending[Overview](/docs/extending/)Extensions[Extension anatomy](/docs/extending/extensions/anatomy/)[Schema composition](/docs/extending/extensions/schema-composition/)[Custom classes](/docs/extending/extensions/classes/)[Custom formats](/docs/extending/extensions/formats/)[Capability methods](/docs/extending/extensions/capabilities/)[Project sections](/docs/extending/extensions/project-sections/)[Server mounts](/docs/extending/extensions/server/)[Connectors](/docs/extending/extensions/connectors/)[Search indexes](/docs/extending/extensions/search/)[Security and secrets](/docs/extending/extensions/security/)[Tutorial: a TOML format](/docs/extending/extensions/tutorial-toml-format/)[Tutorial: a guestbook](/docs/extending/extensions/tutorial-guestbook/)[First-party extensions](/docs/extending/extensions/first-party/)Embedding[Overview](/docs/extending/embedding/)[Hosting the Studio assets](/docs/extending/embedding/hosting/)[Writing a platform adapter](/docs/extending/embedding/platform-adapter/)[The backend protocol](/docs/extending/embedding/backend-protocol/)[Dev server internals](/docs/extending/embedding/dev-server/)[Embedding the runtime in your app](/docs/extending/embedding/runtime-host/)[Writing assistant tools](/docs/extending/embedding/assistant-harness/)UI kit[The Jx UI kit](/docs/extending/ui-kit/)Reference[Protocol routes](/docs/extending/reference/studio-routes/)[Implementation status](/docs/extending/reference/implementation-status/)[Spec changelog](/docs/extending/reference/spec-changelog/)[Standards alignment](/docs/extending/reference/standards/)Contributing[Working in the monorepo](/docs/extending/contributing/monorepo/)[Contributing to these docs](/docs/extending/contributing/docs/)[AI assistant evals](/docs/extending/contributing/ai-evals/) # Elements > **Studio writes this format for you.** Every element you place on the canvas and edit in the [Properties panel](/docs/studio/design/properties) is stored as one of these objects, and this page documents what lands in the file. An element definition is a JSON object describing one DOM element. Its keys are the element's real DOM property names, set directly on the created element with no translation layer in between. If a property exists on the DOM element, you can set it here. ```json shiki ``` ## DOM properties Property names follow the DOM, not HTML source: `className` (not `class`), `textContent` (not inner text), `tabIndex` (not `tabindex`). Any string-valued property may contain a ${} template for a reactive value (see [Reactivity](/docs/framework/concepts/reactivity)), or be an object with `$ref` bound to state (see [References](/docs/framework/concepts/references)): ```json shiki ``` Two properties are **protected**: `id` and `tagName` identify the element and may not be set via `$ref` bindings. ## Custom attributes Anything that is not a standard DOM property (`data-*`, `aria-*`, `slot`) goes in the `attributes` object, written exactly as it appears in HTML: ```json shiki ``` Attribute values may also be reactive templates ("aria-label": "${state.count} unread messages"). ### Boolean values An attribute value of `true` or `false`, written directly or resolved from a ${...} template, is spelled the way the attribute itself is read. HTML has two rules here, and Jx picks the right one from the attribute name, so conditional markup is just a boolean: ```json shiki ``` **Presence attributes** are read by presence alone: `open`, `disabled`, `checked`, `hidden`, `required`, `selected` and the rest of the HTML boolean family. `true` writes the bare name, `false` removes the attribute entirely: ```html shiki ``` Warning Never write `"open": "false"` as a string. HTML counts *any* value as present, `"false"` included, so `
` is an **open**`
` . This is the reason a boolean is not stringified. **Enumerated attributes** carry the word in their text and treat an empty value as unset. Every `aria-*` attribute is one, along with `contenteditable`, `draggable` and `spellcheck`. A boolean writes the word for these, in both directions: ```json shiki ``` ```html shiki ``` `popover` sits between the two families and is the one attribute worth naming. It is enumerated (its keywords are `auto`, `manual` and `hint`), but an empty value means `auto` rather than unset, so a boolean `true` writing the bare name happens to be right. A value the browser does not recognise falls back to `manual`, which gives up closing on Escape and on a click outside without saying so, and `popover="true"` is such a value. Write the keyword: ```json shiki ``` Studio reports a boolean `popover` as a problem rather than correcting it. See [Popovers and overlays](/docs/framework/concepts/overlays). That distinction matters for accessibility: a bare `aria-hidden` is *not* hidden, and an omitted `contenteditable` means "inherit from the parent" rather than `false`. Writing either as a presence attribute would silently invert it. **A value of `null` removes the attribute.** A `$ref` to a missing entry, or a template whose single expression yields `null` or `undefined`, takes the attribute away rather than writing an empty string. That is how one template carries an attribute that exists only in some states: ```json shiki ``` A **string** is never reinterpreted in either family. `"aria-current": "false"` stays exactly that, which is how you write the not-the-current-page marker beside `"aria-current": "page"`. The compiled page and the live runtime apply the same rule, so a prerendered element does not change meaning when it hydrates. ## Children `children` is an array of element definitions, rendered in order: ```json shiki ``` A `children` array may freely mix element objects, bare text nodes, and [repeaters](/docs/framework/concepts/lists) (`$prototype: "Array"` members) or [switches](/docs/framework/concepts/switching). ## Text nodes Bare strings and numbers are valid `children` items. They produce DOM `Text` nodes directly, with no wrapper element. This is how text with inline markup is written: ```json shiki ``` That is the HTML `

Hello world!

`. Template strings in text nodes are reactive: { "children": \["Welcome, ${state.name}!"] }. ## Slots Custom elements use the standard HTML `slot` mechanism for content composition. A component's template places `` elements; content the instance provides is distributed to them by `name`: ```json shiki ``` A slot's own `children` act as fallback content, kept when the instance provides nothing for it. Whitespace between children is not content, so a component given only named children still shows its unnamed slot's fallback. When two slots share a name, the first one in the template takes the children and the second shows its fallback. A slot written directly inside another component's children passes on what it receives, placed by its own `slot` attribute. The `` itself leaves nothing behind. What the instance provided stands exactly where the slot was written, as a direct child of whatever contained it. That is what lets a component style what it was given: a rule like `"& > [part=\"body\"] > b"` reaches a slotted ``, because the `` really is a child of that part. ## Annotations Any element may carry `$title` and `$description`, developer-facing labels that never reach the DOM: ```json shiki ``` Studio's [Outline panel](/docs/studio/design/layers) shows `$title` as the element's display name. ## How it works The runtime creates the element with `document.createElement(tagName)`, assigns each listed property directly on the element object, and writes `attributes` entries with `setAttribute`. Properties whose values are templates or `$ref` bindings are wrapped in reactive effects, so the DOM updates whenever the underlying state changes. Slot distribution is manual light-DOM distribution: host children are captured before the template renders, then each `` is replaced by the children matching it, or by its own fallback children when nothing matches. A built page distributes the same way, in the component's module and in its prerendered HTML. ## Rules - `tagName` is required on every element definition. - `id` and `tagName` are protected, and never settable via `$ref`. - Standard DOM properties go at the top level; everything else (`data-*`, `aria-*`, `slot`) goes in `attributes`. - Bare strings and numbers in `children` become text nodes; when *all* children are bare strings with no element siblings, prefer `textContent` instead. - `$title` and `$description` are plain strings: not reactive, not `$ref`-resolvable, never applied to the DOM. - Styling does not use DOM properties. The `style` object has its own grammar, covered in [Styling](/docs/framework/concepts/styling). ## Related - [Documents](/docs/framework/concepts/documents): the file these objects live in - [Reactivity](/docs/framework/concepts/reactivity): ${} templates in any string property - [Styling](/docs/framework/concepts/styling): the `style` object, nesting, and breakpoints - [Lists and iteration](/docs/framework/concepts/lists): repeaters inside `children` - [Properties panel](/docs/studio/design/properties): the Studio surface that edits these objects ✕ Start here[Overview](/docs/start/)Get started[Install Jx Studio](/docs/start/install/)[Your first project](/docs/start/first-project/)[A tour of Jx Studio](/docs/start/studio-tour/)Tutorials[Tutorial: interactive component](/docs/start/first-component/)[Tutorial: blog with collections](/docs/start/first-collection/)[Video tutorials](/docs/start/videos/)Coming from another tool[Coming from WordPress](/docs/start/coming-from-wordpress/)[Coming from Webflow or Framer](/docs/start/coming-from-webflow/)[Coming from Wix or Squarespace](/docs/start/coming-from-wix/)[Coming from Lovable or Builder.io](/docs/start/coming-from-ai-builders/)Studio[Overview](/docs/studio/)[The desktop app](/docs/studio/desktop/)The workspace[Overview](/docs/studio/interface/)[Welcome screen](/docs/studio/interface/welcome-screen/)[Editors and views](/docs/studio/interface/modes/)[The canvas](/docs/studio/interface/canvas/)[Documents and panes](/docs/studio/interface/tabs/)[Quick Access](/docs/studio/interface/quick-access/)[Keyboard shortcuts](/docs/studio/interface/shortcuts/)[Preferences](/docs/studio/interface/preferences/)[Languages](/docs/studio/interface/languages/)[Problems and progress](/docs/studio/interface/problems-and-progress/)[Commands](/docs/studio/interface/commands/)Projects[Overview](/docs/studio/projects/)[Create a project](/docs/studio/projects/create/)[Pages, layouts, components](/docs/studio/projects/pages-layouts-components/)[The Content workspace](/docs/studio/projects/browse/)[Starter templates](/docs/studio/projects/starters/)[Media](/docs/studio/projects/media/)[Content types](/docs/studio/projects/content-types/)[Project settings](/docs/studio/projects/settings/)[Dependencies and imports](/docs/studio/projects/dependencies/)Edit mode[Overview](/docs/studio/editing/)[Writing and formatting](/docs/studio/editing/writing/)[Slash commands](/docs/studio/editing/slash-commands/)[Frontmatter and metadata](/docs/studio/editing/frontmatter/)[Grid mode](/docs/studio/editing/grid/)Design mode[Overview](/docs/studio/design/)[Outline](/docs/studio/design/layers/)[Insert](/docs/studio/design/elements/)[Content tab](/docs/studio/design/properties/)[Style inspector](/docs/studio/design/style-inspector/)[Breakpoints](/docs/studio/design/breakpoints/)[States and selectors](/docs/studio/design/states-and-selectors/)[Design tokens](/docs/studio/design/tokens/)[Project Styles](/docs/studio/design/stylebook/)[Working with components](/docs/studio/design/components/)[Repeaters](/docs/studio/design/repeaters/)Logic[Overview](/docs/studio/logic/)[Formulas and expressions](/docs/studio/logic/formulas/)[Formula workspace](/docs/studio/logic/formula-workspace/)[Statements](/docs/studio/logic/statements/)[Logic tab](/docs/studio/logic/events/)[Data](/docs/studio/logic/data/)[Data sources](/docs/studio/logic/data-sources/)[Code editing](/docs/studio/logic/code/)Databases[Overview](/docs/studio/data/)[Connections](/docs/studio/data/connections/)[Data tables](/docs/studio/data/tables/)[Data grid](/docs/studio/data/grid/)[Auth and secrets](/docs/studio/data/auth-and-secrets/)AI assistant[Overview](/docs/studio/ai/)[The AI assistant](/docs/studio/ai/chat/)[Document assistant](/docs/studio/ai/document-assistant/)Publish[Overview](/docs/studio/publish/)[Source control](/docs/studio/publish/source-control/)[GitHub](/docs/studio/publish/github/)[Cloudflare Pages](/docs/studio/publish/cloudflare/)[Other hosts](/docs/studio/publish/other-hosts/)[Redirects](/docs/studio/publish/redirects/)[Real-time collaboration](/docs/studio/publish/collaboration/)Framework[Overview](/docs/framework/)Concepts[Documents](/docs/framework/concepts/documents/)[Elements](/docs/framework/concepts/elements/)[Components](/docs/framework/concepts/components/)[Props and scope](/docs/framework/concepts/props-and-scope/)[State](/docs/framework/concepts/state/)[Reactivity](/docs/framework/concepts/reactivity/)[References](/docs/framework/concepts/references/)[Expressions](/docs/framework/concepts/expressions/)[Statements](/docs/framework/concepts/statements/)[Functions and sidecars](/docs/framework/concepts/functions/)[Styling](/docs/framework/concepts/styling/)[Color schemes](/docs/framework/concepts/color-schemes/)[Popovers and overlays](/docs/framework/concepts/overlays/)[Accessibility](/docs/framework/concepts/accessibility/)[Lists and iteration](/docs/framework/concepts/lists/)[Data prototypes](/docs/framework/concepts/data-prototypes/)[Timing](/docs/framework/concepts/timing/)[Dynamic switching](/docs/framework/concepts/switching/)[Security](/docs/framework/concepts/security/)Site architecture[Overview](/docs/framework/site/)[project.json](/docs/framework/site/project-json/)[Routing](/docs/framework/site/routing/)[Layouts](/docs/framework/site/layouts/)[Content collections](/docs/framework/site/content-collections/)[Jx Markdown](/docs/framework/site/jx-markdown/)[Obsidian vault as content](/docs/framework/site/obsidian-vault/)[Relationships](/docs/framework/site/relationships/)[SEO and metadata](/docs/framework/site/seo/)[Locales and languages](/docs/framework/site/i18n/)[Images](/docs/framework/site/images/)[Redirects](/docs/framework/site/redirects/)[Feeds](/docs/framework/site/feeds/)[Site search](/docs/framework/site/search/)[Build output and adapters](/docs/framework/site/deployment/)How compilation works[Overview](/docs/framework/build/)[The dev server](/docs/framework/build/dev-server/)[CLI commands](/docs/framework/build/cli/)Working with agents[Overview](/docs/framework/agents/)[Authoring rules for agents](/docs/framework/agents/authoring-rules/)[Machine-readable docs](/docs/framework/agents/machine-readable/)Reference[Overview](/docs/framework/reference/)[Formula catalog](/docs/framework/reference/formulas/)[Operator reference](/docs/framework/reference/operators/)Extending[Overview](/docs/extending/)Extensions[Extension anatomy](/docs/extending/extensions/anatomy/)[Schema composition](/docs/extending/extensions/schema-composition/)[Custom classes](/docs/extending/extensions/classes/)[Custom formats](/docs/extending/extensions/formats/)[Capability methods](/docs/extending/extensions/capabilities/)[Project sections](/docs/extending/extensions/project-sections/)[Server mounts](/docs/extending/extensions/server/)[Connectors](/docs/extending/extensions/connectors/)[Search indexes](/docs/extending/extensions/search/)[Security and secrets](/docs/extending/extensions/security/)[Tutorial: a TOML format](/docs/extending/extensions/tutorial-toml-format/)[Tutorial: a guestbook](/docs/extending/extensions/tutorial-guestbook/)[First-party extensions](/docs/extending/extensions/first-party/)Embedding[Overview](/docs/extending/embedding/)[Hosting the Studio assets](/docs/extending/embedding/hosting/)[Writing a platform adapter](/docs/extending/embedding/platform-adapter/)[The backend protocol](/docs/extending/embedding/backend-protocol/)[Dev server internals](/docs/extending/embedding/dev-server/)[Embedding the runtime in your app](/docs/extending/embedding/runtime-host/)[Writing assistant tools](/docs/extending/embedding/assistant-harness/)UI kit[The Jx UI kit](/docs/extending/ui-kit/)Reference[Protocol routes](/docs/extending/reference/studio-routes/)[Implementation status](/docs/extending/reference/implementation-status/)[Spec changelog](/docs/extending/reference/spec-changelog/)[Standards alignment](/docs/extending/reference/standards/)Contributing[Working in the monorepo](/docs/extending/contributing/monorepo/)[Contributing to these docs](/docs/extending/contributing/docs/)[AI assistant evals](/docs/extending/contributing/ai-evals/) [![Jx Suite](/favicon.svg) Suite](/)The visual IDE for the web. 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