Meaning & Definition
URL (Uniform Resource Locator)
A URL, or Uniform Resource Locator, is a reference or address used to access resources on the internet. It is a string of characters that specifies the location of a resource, such as a web page, a file, or an online service. URLs are fundamental to web browsing and internet navigation, as they provide a standardized way to locate and retrieve content from various servers and websites.
A URL is typically composed of several components, each serving a specific purpose:
- Scheme or Protocol
The scheme or protocol defines the method or protocol used to access the resource. Common schemes include “http://” for Hypertext Transfer Protocol (HTTP), “https://” for HTTP Secure (HTTP over SSL/TLS), “ftp://” for File Transfer Protocol, “mailto:” for email addresses, and “file://” for local files.
- Domain or Host
The domain or host component identifies the location of the resource’s server. It can be in the form of a human-readable domain name (e.g., “www.example.com”) or an IP address (e.g., “192.168.0.1”). In the case of web URLs, this is often preceded by “www” but may include subdomains, such as “blog.example.com.”
- Port (Optional)
The port component, if specified, indicates the network port on which the server is listening. While some schemes have default ports (e.g., 80 for HTTP and 443 for HTTPS), non-standard ports can be specified when necessary (e.g., “http://example.com:8080”).
The path component specifies the location and structure of the resource on the server. It often resembles the directory structure of a file system. For example, in the URL “https://www.example.com/products/electronics/laptops,” “/products/electronics/laptops” is the path to a specific web page or content.
- Query (Optional)
The query component, if present, contains parameters that are used to pass information to the resource. It is preceded by a question mark (“?”) and can include multiple key-value pairs (e.g., “?search=keyword&page=2”).
- Fragment (Optional)
The fragment component, if used, points to a specific section or identifier within the resource. It is preceded by a hash or pound sign (“#”) and is commonly used in web pages to link to specific sections of a document.
Here’s an example of a complete URL: “https://www.example.com:8080/products/electronics/laptops?search=keyword&page=2#section2”
In this example:
- The scheme is “https.”
- The domain or host is “www.example.com,” and the port is “8080.”
- The path is “/products/electronics/laptops.”
- The query is “?search=keyword&page=2.”
- The fragment is “#section2.”
URLs are essential for navigating the internet, as they allow users to access websites, download files, and interact with web services. Web browsers use URLs to retrieve and display web pages, and many other applications rely on URLs to fetch data or resources from remote servers.