[exec]

function fxFade( element, from, to, time, delta, callback ) {
	delta = delta || function (x) {
		return x;
	};
	var IE = document.all && !window.opera,
	start = new Date().getTime();
	if (IE) {
		from *= 100,
		to *= 100;
	}
	element.fadeTimer = setTimeout(function () {
		var progress = (new Date().getTime() - start) / time,
		result = (to - from) * delta(progress) + from;
		if (IE) {
			element.style.filter = "alpha(opacity=" + result + ")";
		} else {
			element.style.opacity = result;
		}
		if (progress < 1) {
			element.fadeTimer = setTimeout(arguments.callee, 10);
		} else {
			callback && callback();
		}
	}, 10);
}

// 1 — начальное значение, 0 — конечное, 1000 — время
fxFade( document.getElementById("foo"), 1, 0, 1000 );