The HTML/CSS/JS platform offered by modern browsers is very powerful and approachable, but the web's security model prevents most platform customizations. Brows

The HTML/CSS/JS platform offered by modern browsers is very powerful and approachable, but the web's security model prevents most platform customizations. Browser-managed navigation, form submission, control appearance, etc, is largely a take-it-or-leave-it proposition. JS frameworks allow front-end developers to get around this limitation by rebuilding parts of the platform as a JavaScript application. For example, if you want to customize how navigation works on your page, you can either use the few, limited hooks offered by the browser (e.g., registering window.onunload callbacks), or you can make navigation an application concern by writing your site as a single-page app. There are plenty of things you just can't do with a framework-less multipage site (like animate transitions between pages) that are possible once you make navigation an application rather than platform concern. I can understand why many enterprise teams choose to use front-end frameworks like React even when it would arguably be faster and easier to just use vanilla JS, as there's a risk someone may need to add functionality that is not supported by the native web platform. For personal projects, though, I use vanilla JS and HTML.