Thank you! it was very useful.
How can I add to this code a duration for the toggle, and put for mouseout a fade, also with duration?

if u need any help, i'm always willing =p

I've started to play around with jQuery a lot more lately and I'm very pleased with it. I'll likely be doing a lot more of the functionality here using it as I get around to it.

jquery is much more efficient with this imo, since you have it, you should use it =p

<button>You cant see <div style='visibility:hidden;'>this</div></button>
<script>
$('button').hover(function(){jQuery(":first-child", this).css('visibility', 'visible');},function(){jQuery(":first-child", this).css('visibility', 'hidden');});</script>

The cool thing about this is the wide range of customization:

<table cellpadding=0 cellspacing=0><tr class='hov'><td>PLATFORMS</td><td style='width:30px; height:30px;'><img class='hidden' src='http://www.hawkee.com/images/bullet_arrow_down.png' /></td></tr></table>

OR

<div class='hov'>Hover<div class='hidden'>I see you!</div></div>

$(document).ready(function() {
    $('.hidden').hide();
    $('.hov').hover(function(){jQuery(".hidden",this).fadeIn();},function(){jQuery(".hidden",this).fadeOut();});
});

live example at http://left4quake.com/this.html
you'll find jquery is the best =]

outcome = unobtrusive lightweight effective dynamic code, also a really cool effect.

Good suggestion Digital, that's another way to do it.

You can also space some lines and change line 4-5 to:

item.style.visibility = (item.style.visibility == 'visible') ? 'hidden' : 'visible';

Yes, the point is to keep the space just as we've done in the site menu above when you hover over a link and the drop down arrow appears.

Your changing the visibility attribute, basically your saying if the visibility is OFF, keep that space but dont show it, if its on USING That space show it..

Visibility is not recommended it. change it to 'display'

Which one is that? And I guess it's best to add it in anyway, so as to cater for all versions.

Then I'm not sure why it made a difference for me, maybe its the version of IE I'm using.

Really? That's odd, several of my scripts have worked without it. I'll bear that in mind when creating more scripts, thanks!

Actually, you need the 'var' because IE errors out if you don't use it. I struggled with this in the past only to realize I had forgotten a var declaration.

Also, the 'var' before the variable name is not necessary, although there's no problem having it, I guess different people prefer doing things differently, it's definitely clearer having it there - but longer.

Thanks, I think it just helps make it more clear and reduces the overall number of characters used.

Nice work, interesting the way you chose to add the document.getELementById to a variable, then seperate for the styles, rather than assign the style to a variable and do:
document.getElementById(obj).style.visibility = style;
But works nicely :-)