HTML Rollover with JS

Hi All,

Ive got this problem with a HTML rollover. For some reason the rollovers stoped working.... but I dont know why:

<a href="index.html" onmouseover="image1.src='images/home_on.gif';"onmouseout="image1.src='images/home_off.gif';"><img name="image1" border="0" src="images/home_off.gif" alt="home...house">

thanks a bunch,
m.