Relative URLs are used to link other pages within the same site. Let's understand this concept in detail.

What are URLs?
URL stands for Uniform Resource Locator. It is the address that identifies a particular resource on the internet. URLs are used to navigate and access web pages, files, and other resources.

What are relative URLs?
Relative URLs are a type of URL that specifies the location of a resource relative to the current page or file. It is a path that is relative to the current location rather than an absolute path that specifies the complete address of a resource.

Advantages of relative URLs:
Relative URLs offer several advantages when it comes to linking pages within the same site:

1. Flexibility: Relative URLs allow for flexibility when moving or restructuring a website. If the structure of the site changes, the relative URLs will still work as they are based on the relative path from the current page.

2. Portability: Relative URLs make it easier to transfer or duplicate a website to a different domain or server. The links will adapt to the new location without needing to be updated.

3. Maintainability: With relative URLs, it is easier to manage and maintain a website. If a page needs to be renamed or moved to a different folder, only the relative link needs to be updated, rather than every single link on the site.

Examples of relative URLs:
Relative URLs are specified using relative path notations. Here are some examples:

- Linking to a page in the same directory: If the current page is "example.com/about.html" and you want to link to "example.com/contact.html", the relative URL would be "contact.html".

- Linking to a page in a subdirectory: If the current page is "example.com/products.html" and you want to link to "example.com/products/category.html", the relative URL would be "category.html" or "products/category.html".

- Linking to a page in the parent directory: If the current page is "example.com/products/category.html" and you want to link to "example.com/products.html", the relative URL would be "../products.html".

In conclusion, relative URLs are used to link other pages within the same site. They provide flexibility, portability, and maintainability to the website structure, making it easier to manage and update links.