--- sidebar_position: 3 --- # Browser Support The browsers that we support are specified in the `.browserlistrc` file located in the `platform/viewer` project. While we leverage the latest language features when writing code, we rely on `babel` to _transpile_ our code so that it can run in the browsers that we support. ## In Practice The OHIF Viewer is capable of _running_ on: - IE 11 - FireFox - Chrome - Safari - Edge However, we do not have the resources to adequately test and maintain bug free functionality across all of these. In order to push web based medical imaging forward, we focus our development efforts on recent version of modern evergreen browsers. Our support of older browsers equates to our willingness to review PRs for bug fixes, and target their minimum JS support whenever possible. ### Polyfills > A polyfill, or polyfiller, is a piece of code (or plugin) that provides the > technology that you, the developer, expect the browser to provide natively. An example of a polyfill is that you expect `Array.prototype.filter` to exist, but for some reason, the browser that's being used has not implemented that language feature yet. Our earlier transpilation will rectify _syntax_ discrepencies, but unimplemented features require a "temporary" implementation. That's where polyfills step in. You can utilize a service like [polyfill.io](https://polyfill.io/v3/) to auto-detect and apply polyfills as needed, or you can update the PWA build to include polyfill's in your bundle by incorporating [core-js][core-js] [core-js]: https://github.com/zloirock/core-js/blob/master/docs/2019-03-19-core-js-3-babel-and-a-look-into-the-future.md