changing images in a js function?

I suspect that the answer to this question is no as images are loaded when the page loads. However, I have a bit of XSLT that runs a javascript function. The purpose of the function is that when the image is clicked it's image changes from a minus to a plus. It doesn't work, does anyone have some JS that does?

If this cannot be done than is it possible to change the text between the <a> and </a> on an anchor tag, as I could use that instead.

Uh, of course that can be done! how do you think rollovers work?<img src="plus_sign.gif" onClick="this.src='minus_sign.gif'" />Unless I misunderstood you?

Beautiful!

Thanks very much.