Dart supports the web as one of its core platforms. Dart-to-JavaScript compilers are available both for development (with a quick edit-refresh cycle) and for production (with a focus on code size and speed).
In addition to compilers, the Dart web platform provides core libraries, access to the DOM (Document Object Model), and interoperability for calling JavaScript from Dart.
You have the option of using Dart web with a higher-level web app framework. Several web apps at Google (including the Google Ads front end formerly known as AdWords) are built using AngularDart. Many apps that support both web and mobile are built using Flutter and Flutter web support. AngularDart, Flutter web support, and other web app frameworks for Dart are powered by the Dart web platform.
Flutter Gallery, running in a web browser