URL

URL (Uniform Resource Locator) is the address of a resource on the web. It tells the browser where to find and how to access a specific page or file.

URL Structure

A URL consists of several parts:

https://example.com:443/path/to/page?query=value#fragment

• Protocol (https://) — the communication method (HTTP, HTTPS, FTP).
• Domain (example.com) — the server address.
• Port (:443) — optional, specifies the connection port (default: 80 for HTTP, 443 for HTTPS).
• Path (/path/to/page) — the location of the resource on the server.
• Query String (?query=value) — optional parameters passed to the server.
• Fragment (#fragment) — optional, points to a specific section within the page (client-side only).

Common Protocols

• http:// — unencrypted web traffic.
• https:// — encrypted web traffic (TLS/SSL).
• file:// — local file system access.
• data: — embedded data (base64-encoded content).

URL Encoding

Special characters must be encoded:

• Space becomes %20 or +.
• # becomes %23.
• & becomes %26.

Relative vs Absolute URLs

• Absolute: https://example.com/page — complete address.
• Relative: /page or ../page — resolved relative to current page URL.