/* ======================================================
 * 程序名: Maple Web.CMS (平滑对联广告)
 * 当前版本: v1.0.0 beta
 * 作者: 云端o枫o0
 * 联系邮件: [email]lantk@126.com[/email]
 * 腾讯QQ: 570389199
 * 网站地址: [url]http://lantk.588.net[/url]
 * 最后更新: 2007-11-10
 * 注释: 此段代码不会影响程序执行，请尊重作者的劳动，谢谢。
 * =======================================================
 */

function couplet(){
	if(arguments.length>=1)	this.objID = document.getElementById(arguments[0]);
	if(arguments.length>=2)	this.divTop = arguments[1];
	if(arguments.length>=3) this.divPlane = arguments[2];
	if(arguments.length>=4)	this.scrollDelay = arguments[4];
	if(arguments.length>=5) this.waitTime = arguments[5];

	if(!this.objID){
		alert("对象名【"+ arguments[0] +"】无效，对联无法初始化，请检查对象名称是否正确！");
		this.objID = null; return;
	}else{
		this.objID.style.position="absolute";
		this.objID.style.display="block";
		this.objID.style.zIndex=9999;
	}

	if("" == this.objID.style.top){
		if(isNaN(this.divTop)){
			alert("对象垂直位置(top)参数必须为数字。"); return;
		}else{
			this.objID.style.top = this.divTop+"px";
		}
	}

	if("" == this.objID.style.left && "" == this.objID.style.right){
		if(isNaN(this.divPlane)){
			alert("对象水平位置(left||right)参数必须为数字。"); return;
		}

		if(this.divPlane>0) this.objID.style.left = this.divPlane+"px";
		if(this.divPlane<0) this.objID.style.right = Math.abs(this.divPlane)+"px";
	}

	if(this.scrollDelay<15 || isNaN(this.scrollDelay)) this.scrollDelay = 15;
	if(this.waitTime<500 || isNaN(this.waitTime)) this.waitTime = 500;
	if(arguments.length>=1) this.start();
}

couplet.prototype.start = function(){
	if(null == this.objID) return;

	var objCouplet = this;

	timer = this.scrollDelay;
	objCouplet.lastScrollY = 0;
	objCouplet.timerID = null;

	objCouplet.startID = function(){
		if("block" == objCouplet.objID.style.display){
			objCouplet.run();
		}else{
			clearInterval(objCouplet.timerID);
		}
	}

	objCouplet.Begin = function(){
		objCouplet.timerID = setInterval(objCouplet.startID,timer);
	}
	
	setTimeout(objCouplet.Begin,this.waitTime);
}

couplet.prototype.run = function(){
	if(document.documentElement && document.documentElement.scrollTop){
		uu_scrY = parseFloat(document.documentElement.scrollTop);
	}else if(document.body){
		uu_scrY = parseFloat(document.body.scrollTop);
	}

	uu_divX = parseFloat(this.objID.style.top.replace("px",""));

	uu_curTop = .1 * (uu_scrY - this.lastScrollY);
	uu_curTop = uu_curTop>0?Math.ceil(uu_curTop):Math.floor(uu_curTop);

	this.objID.style.top = parseFloat(uu_divX + uu_curTop) + "px";
	this.lastScrollY += uu_curTop; 
}