var overOpacity = 80;
var currTrans = {};

function changeOpacity(transparent, opacity)
{
	if (navigator.appName.indexOf("Microsoft")!= -1 && parseInt(navigator.appVersion) >= 4) {
		transparent.style.filter = 'alpha(opacity='+opacity+')'; 
	} else {
		transparent.style.MozOpacity = opacity / 100;
		transparent.style.khtmlOpacity = opacity/100;
		transparent.style.opacity = opacity/100;	
	}
}

function toggleOpacity(div) {
	if(div) {
		if(!currTrans[div.id]) {
			currTrans[div.id] = true;
			changeOpacity(div, overOpacity);
		} else {
			currTrans[div.id] = null;
			changeOpacity(div, 100);
		}
	}
}