The whole point of an anchor link is to scroll a page to a particular point. So if you don't want that to happen, you need to attach an onclick handler and return false. Even just adding it as an attribute should work:

button 1

A side of effect of the above is that the URL itself won't change, since returning false will cancel the event. So since you want the URL to actually change, you can set the window.location.hash variable to the value that you want (that is the only property of the URL that you can change without the browser forcing a reload). You can probably attach an event handler and call something like window.location.hash = this.id though I'm not sure how mootools handles events.

(Also you need all of the IDs to be unique)

http://stackoverflow.com/questions/1218034/html-anchor-link-with-no-scroll-or-jump