Most of the web applications are written with SPA frameworks such as Angular, React, Vue.js, etc. The problem with these SPAs is that the single page is loaded in the browser once and then the framework will take care of all the routing among pages and gives the impression to the user that it is a multi-page application. When you refresh your page in the browser that single page called index.html is reloaded and you will lose the entire state of the application.
