I actually use other JavaScript libraries, which handle opacity better than my class. If I had known more about JavaScript and programming in general, then this class would never have been created and this post would have been about using that JS library instead.

One fix though for you. Your fadeOut doesn’t work because the opacity value isn’t being set in the setOpacity function.

So change setOpacity to:

Opacity.prototype.setOpacity = function(value)
{
if(value == 0) {
this.style.display = ‘none’;
} else {
this.style.display = ‘block’;
}

this.opacity = value;
this.style.opacity = (value / 100);
this.style.MozOpacity = (value / 100);
this.style.KhtmlOpacity = (value / 100);
this.style.filter = "alpha(opacity=" + value + ")";

}

—————

What I did instead of having it in the is place it in the page so that it would start as soon as possible.

<script src="path/to/script.js" language="javascript"></script>
<p id="changeOpacity" onmouseover="var opacity = new Opacity(this); opacity.setOpacity(0); opacity.FadeIn();">
    Text here.
</p>