URLs, query parameters, and encoding

What you will build

Build request URLs safely with URL and URLSearchParams.

Understand the idea first

Build request URLs safely with URL and URLSearchParams.

Build it step by step

const url = new URL('https://api.example.com/search');
url.searchParams.set('q', 'HTML 表单');
url.searchParams.set('limit', '5');
console.log(url.toString());

1. Open the previous project and record its result.
2. Type the example and complete: Build a URL with a Chinese query, page, and limit, then read each parameter back.
3. Change one input, predict, then verify.
4. Create and repair: Do not concatenate spaces, ampersands, or question marks manually.

Read the important lines

• Build request URLs safely with URL and URLSearchParams.
• Read input, processing, and output separately.
• Verify another input and an edge case.

Common mistakes and what to check

Practice without copying

Build a URL with a Chinese query, page, and limit, then read each parameter back.

Completion check

• I produced the required visible result
• I can explain the input, processing, and output
• I tested normal, edge, and failure cases