From Xojo Documentation

Property (As WebPage )
aWebSession.HashTag = newWebPageValue
WebPageValue = aWebSession.HashTag

New in 2011r2

Supported for all project types and targets.

A tag associated with a bookmarked page.

Hash Tags are also called anchors or URL fragments.The developer may change this at any time and the browser's URL field will update immediately without causing a page reload. If the user creates a bookmark, any tag supplied will be saved with it. The developer can read this value in the Session.Open event and display different content accordingly.