HTML 11

HTML 11 extension provides tool windows in Visual Studio 2022/2019/2017 showing preview of static and dynamic web pages you are currently editing, on desktop and mobile devices.

Static .html pages

The preview is updated as you type. When you change a .css or a .js file referenced in the HTML document, the preview is updated after you save the referenced file.

Razor .cshtml pages in ASP.NET Core 2.1/3.0 web application

MVC view .cshtml pages in ASP.NET Core 2.1/3.0 web application

.razor pages in Blazor app

Web Forms .aspx pages in ASP.NET web application

MVC view .cshtml/.vbhtml pages in ASP.NET web application

While the web application server is running in IIS Express, the preview is updated when you save a document. When the server is stopped, the preview is no longer updated and a red border is displayed around the preview area.

Getting started

To initially open HTML 11 tool windows, select Desktop preview or Mobile preview in the main HTML11 menu:

You can position opened tool windows alongside the HTML editor or outside the main Visual Studio window, e.g. on a second monitor.

HTML is rendered using Chromium Embedded Framework v75.

How it works

Static .html pages and associated resources (images, styles, scripts) are loaded by the embedded Chromium browser directly from the disk. For the live preview, page content is provided from a memory buffer.

To show preview for dynamic pages, you need to start the web application (usually pressing Ctrl + F5). HTML 11 finds App/Project URL in web server settings (usually http://localhost:[random-port]), adds the file path to it and opens the preview. When you change and save a page, Visual Studio recompiles it on save, updates the application on the fly, HTML 11 updates the preview and you see the updated page.