Hi Martin -
If you want to share a Tableau visualization and you want that sharing to happen in the browser, you do so by publishing the viz to either Tableau Server, or Tableau Public.
Once published to Tableau Server / Tableau Public, you can get an "embed" tag which you can drop in an HTML page. When the HTML page is opened, the visualization is rendered on Tableau Server / Tableau Public, and then displayed as an embedded frame inside your HTML page.
Hope this helps!