Master programming syntax, solve interactive challenges & run live code in Syntaxis Explore Arena →

menu_book Course Curriculum (Svelte 5) expand_more

Component Syntax

SFC anatomy Markup expressions If blocks Each blocks Await blocks Class directives Style directives Event handlers

Runes & Reactivity

$state $derived $effect $props $bindable Reactive collections State ownership Deep reactivity

Composition

Props Callback props Bindings Snippets {@render} Context Actions DOM references

Motion & Lifecycle

Mounting tick Transitions Custom transitions Animations Crossfade Motion preferences Browser-only code

SvelteKit Routing

File-based routes Layouts Load functions Form actions Server routes Error pages Cookies Environment modules

Production

Server-only modules Validation SSR and hydration Prerendering Adapters Testing Performance budgets Deployment architecture

Svelte 5 / Motion & Lifecycle

Browser-only code

Learn Browser-only code in Svelte 5 with a dedicated explanation, a concept-specific example, a production caution, and a mastery check.

12 min read • Intermediate

svelte-5-032.svelte

svelte

<script>import { browser } from "$app/environment";if(browser){console.log(localStorage.getItem("theme"))}</script>

What to watch

Content source & attribution

Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

Browser-only code Mastery Check →

Motion preferences

File-based routes