Playground workflow

Last reviewed Jun 1, 2026 Content v20260601

Track mode

client_jquery

Means

In-browser jQuery

Reading

~1 min

Level

beginner

This lesson

This lesson teaches Playground workflow: the concepts, APIs, and habits you need before advancing in jQuery.

Without Playground workflow, you will struggle to read or extend jQuery codebases and playground exercises.

You will apply Playground workflow in contexts like: WordPress themes, admin panels, older SPAs, and pages awaiting incremental modernization.

Write JavaScript, click Run—jQuery 3.7 loads from CDN; use mountApp(function($) { ... }) on #playground-root when the DOM is ready; printOutput feeds the terminal.

At the start of the track—complete before JSX-heavy lessons that assume you understand the playground.

Click Run in browser to execute JavaScript against a sandboxed iframe. jQuery loads automatically; you do not import it.

Terminal vs preview

printOutput(value) — inspect objects, Ajax payloads, or debug counters
mountApp(function ($) { ... }) — runs inside $(function(){ ... }) when DOM is ready

Demo elements

Target #playground-root, #demo-text, #demo-btn, and #demo-card—they exist in every preview.

Self-check

When should you prefer printOutput over changing the preview?
What happens if jQuery CDN fails?

Challenge

Run preview

Click Run in browser.
Confirm #demo-text updates.

Done when: preview text changes and terminal logs mountApp guidance.

Playground

Runs in your browser in a sandboxed frame. Backend runners appear when this track’s profile allows them.

Discussion

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Starter discussion topics

mountApp callback?
Demo elements used?

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