function FloatAd() {
	this.ID = document.getElementById(arguments[0]);
	if (!this.ID) {
		return ;
	}
	if (typeof(arguments[1]) == "string" && arguments[1] == "bottom") {
		this.ID.style.top = document.body.scrollTop + (document.documentElement.clientHeight ? document.documentElement.clientHeight:document.body.clientHeight) - parseInt(this.ID.style.height) - parseInt(this.ID.style.bottom) + 'px';
	}
	this.adlastScrollY = 0;
}

FloatAd.prototype.start = function() {
	var diffY;
	if (document.documentElement && document.documentElement.scrollTop) {
		diffY = document.documentElement.scrollTop;
	} else if (document.body) {
		diffY = document.body.scrollTop;
	}
	percent = 0.1 * (diffY - this.adlastScrollY); 
	if(percent > 0) {
		percent = Math.ceil(percent); 
	} else {
		percent = Math.floor(percent); 
	}
	this.ID.style.top = parseInt(this.ID.style.top) + percent + "px";
	this.adlastScrollY = this.adlastScrollY + percent; 
}