In the early days of the web, pages were static, and changing content required navigation to a new page (url). Then JavaScript took off and you could dynamically change content on a given page, even reload data without navigating/refreshing. In the extreme, frameworks like react were developed, where you no longer have pages at all. The entire website is rendered on the same page using JavaScript to load all the content on the fly.
In the early days of the web, pages were static, and changing content required navigation to a new page (url). Then JavaScript took off and you could dynamically change content on a given page, even reload data without navigating/refreshing. In the extreme, frameworks like react were developed, where you no longer have pages at all. The entire website is rendered on the same page using JavaScript to load all the content on the fly.