There might be some confusion on the two sorts of hyperlinks. A hyperlink in Tk has nothing do do with hyperlinks in a browser. The only thing they share in common is that something happens when you click on a piece of text (or picture).

tagBind knows nothing of the web; it only allows you to bind some action with clicking on the text. That action is up to you. Typically, tagBind is used to link different parts of a long text, as in a table of contents. But you could certainly use it to open a page on a browser.

There are a couple of ways to do that. One is to simply invoke the browser with a system statement. Another is to communicate with the browser using some IPC like Applescript on the Mac of OLE on Windows.