Javascript breadcrumbs from url

1. What are URL breadcrumbs?
2. When should you not use breadcrumbs?

What are URL breadcrumbs?

Websites. Breadcrumbs typically appear horizontally across the top of a Web page, often below title bars or headers. They provide links back to each previous page the user navigated through to get to the current page or—in hierarchical site structures—the parent pages of the current one.

When should you not use breadcrumbs?

Breadcrumbs aren't necessary (or useful) for sites with flat hierarchies that are only 1 or 2 levels deep, or sites that are linear in structure.