<script type="text/javascript">
function fader() {
  var Opacity = document.getElementById('fadeBox').style.opacity;
  Opacity + 0.2;
}
setInterval("fader()", 1500);
</script>
<div style="background:blue;color:white;padding:10px;width:300px;opacity:0.1;" id="fadeBox">Hi there...</div>



.

It's supposed to increase the opacity of fadeBox every 1.5 seconds... But it doesn't

Your script never writes the new value back to the element, it simply reads the existing value from the element each time.

Oh and of course it will need a check so the final value does not go over the maximum value.

So ummmm how would I fix it? I am a noob at js

One of my "playing pages"

http://www.modtalk.co.uk/_site/code/css/opacity/

I keep meaning to add the crossbrowser bits (well the Internet Exploder bits)

	var fadeInId = 0;
	var fadeOutId = 0;
	var opac = 0;
	var e = null;
	
function fadeIn() {
	if(opac < 1) {
  		opac = opac + 0.01;
	} else {
		clearInterval(fadeInId);
		fadeOutId = setInterval("fadeOut()", 100);
		e.innerHTML = "Fade Out";
	}

	e.style.opacity = opac;
}
function fadeOut() {

	if(opac > 0) {
  		opac = opac - 0.01;
	} else {
		clearInterval(fadeOutId);
		fadeInId = setInterval("fadeIn()", 100);
		e.innerHTML = "Fade In";
	}
	e.style.opacity = opac;
}

function fadeInit(eID) {
	e = document.getElementById(eID);
	fadeInId = setInterval("fadeIn()", 100);
}

jquery? mootools? PPPPFFTTTT!!!!