How to go to anchor tag in scrollable div without having the whole browser jump down?

I'm building a simple glossary widget as part of a larger project for a client. The content of the glossary is enclosed within a scrollable div (overflow:auto). Each letter has an anchor tag associated with it (#a, #b, #c, etc). Above the scrollable div is a div which contains every letter of the alphabet. Clicking on one of these letters takes the user down to that letter's definitions in the scrollable div. This works, but an unintended side effect is that the entire window jumps down to the anchor, which is confusing and annoying to the user.

Here is the widget, stripped down a bit and with a bunch of <br />'s to let you see what I mean.

http://www.nitrohandsome.com/clients/topics/glossary-widget/

I had tried a few different javascript ideas I cobbled together from some Googling, but nothing was working, so i just got rid of everything but the actual go to anchor code (I'm a pretty big JS newbie). So开发者_如何学JAVA right now, clicking on any of the letters executes this javascript function, with the anchor tag passed to it:

    function jumpToAnchor(myAnchor) {
   window.location = String(window.location).replace(/\#.*$/, "") + myAnchor;
  }

How can I pull this off so the overall window doesn't jump each time a link is clicked?

Thanks in advance!

If you're using jQuery, you can try the scrollTo plugin. Also, to edit just the hash portion or the URL, you can just do

function jumpToAnchor(myAnchor) {
   window.location.hash = myAnchor;
}

Try to use IFrame instead of Div or create a specific function using ScrollBy.