Using the "#" character as a placeholder basically makes the link "active." The browser interprets it as a tag that points to something else. If href is empty, the browser will assume the a tag is just another tag.
A way around that is to assign some CSS to a different tag that emulates the same functionality of the a tag. On hover, change the mouse, underline, change color, etc. You can easily change the window status and make it seem like the user is clicking on a link when in reality they aren't clicking a link so much as making a click event.
In fact, that's the better option, because running only a JS function through event binding that can't be used without JavaScript shouldn't be considered a link in the first place.
