인터랙티브 기능과 API

Write vanilla JavaScript to fetch data from a REST API:

API endpoint: [URL or describe the API]
Expected response format: JSON array of objects with [describe fields]

Requirements:
- Use async/await with fetch()
- Show a loading indicator while fetching
- Handle HTTP errors (check response.ok)
- Handle network errors (try-catch around the fetch)
- Display data in the page using safe DOM methods (createElement + textContent)
- Show a user-friendly error message if the fetch fails
- Add a timeout (abort after 10 seconds using AbortController)

Vanilla JavaScript, no dependencies.

Write vanilla JavaScript to manage UI states for an API-powered feature:

States to handle:
1. Loading: Show a spinner/skeleton while data loads
2. Success: Display the data
3. Error: Show a friendly message with a retry button
4. Empty: Show a "no results" message when the API returns an empty array

Requirements:
- Single function that manages state transitions
- Retry button re-fetches the data
- Loading spinner is accessible (aria-live="polite" announcement)
- Error messages don't expose technical details to users

Provide the HTML structure, CSS for each state, and JavaScript.

Write a real-time search filter in vanilla JavaScript:

Data: An array of objects displayed as cards on the page
Search behavior:
- Filter as the user types (debounced, 300ms delay)
- Search across multiple fields: [title, description, category]
- Case-insensitive matching
- Show result count ("Showing X of Y items")
- Show "No results" message when nothing matches
- Clear button to reset the search

Requirements:
- Debounce the input handler (don't filter on every keystroke)
- Highlight matching text in results (wrap matches in a mark element)
- Maintain URL state (add search query as URL parameter so it survives refresh)
- Accessible: announce result count changes to screen readers

Vanilla JavaScript, no dependencies.

Write a filter system for a listing page:

Filter types:
- Category (checkboxes, multiple selection)
- Difficulty (radio buttons, single selection)
- Sort (dropdown: newest, oldest, alphabetical)

Requirements:
- Filters combine with AND logic (category AND difficulty)
- URL updates with filter state (shareable filter URLs)
- Active filter count displayed ("3 filters active")
- "Clear all filters" button
- Smooth transition when items show/hide
- Filter counts update to show available items per option

Vanilla JavaScript, no dependencies.

Write an accessible tabs component in vanilla JavaScript:

Requirements:
- Tab list with role="tablist"
- Tab buttons with role="tab", aria-selected, aria-controls
- Tab panels with role="tabpanel", aria-labelledby
- Keyboard navigation: Arrow keys move between tabs, Enter/Space selects
- Only the selected tab panel is visible
- Support for dynamic tab content (loaded on tab switch)

Follow WAI-ARIA Tabs pattern. Vanilla JavaScript, no dependencies.

Write an accessible modal dialog in vanilla JavaScript:

Requirements:
- Opens on trigger button click
- Traps focus inside the modal (Tab cycles through modal elements only)
- Closes on Escape key, overlay click, and close button
- Returns focus to trigger button when closed
- Uses role="dialog" and aria-modal="true"
- Prevents background scroll when open
- Smooth open/close animation with CSS

Follow WAI-ARIA Dialog pattern. Vanilla JavaScript, no dependencies.