// JavaScript Document
function quickscroll(variableName/*as String*/, object, scrollUntil, scrollHow, amount, speed){
	window[variableName]=this;/*variable MUST be window scoped: this line ensures it is*/
	this.object=(typeof object == "object") ? object : 
	(typeof object == "string")? document.getElementById(object):document.getElementsByTagName("BODY")[0]/*if argument object is bypassed, object defaults to body*/;
	
	var position=(this.object.currentStyle)? this.object.currentStyle["position"] : document.defaultView.getComputedStyle(this.object, null).getPropertyValue("position");
	position=(position) ? position.toLowerCase() : position;
	if(position!="absolute" && position!="relative"){
		this.object.style.position="relative";/*wants a position*/
	};
	
	var overflow=(this.object.currentStyle)? this.object.currentStyle["overflow"] : document.defaultView.getComputedStyle(this.object, null).getPropertyValue("overflow");
	overflow=(overflow) ? overflow.toLowerCase() : overflow;
	if(overflow!="auto" && overflow!="scroll"){
		this.object.style.overflow="hidden";/*wants an overflow*/
	};
	
	this.scrollUntil=scrollUntil;
	
	scrollHow=parseFloat(scrollHow)||0;/*must be a number*/
	if(!scrollHow){ 
		this.position="Top"; 
		this.dimension="Height"; 
	} else { 
		this.position="Left"; 
		this.dimension="Width"; 
	};
	
	this.amount=parseFloat(amount)||20;
	this.speed=parseFloat(speed)||20;
	this.timer=0;
	
	/***** METHOD private *****/
	this.afterLoad=function(){
	this.scrollHow="scroll"+this.position;
		if(typeof this.scrollUntil == "object"){
		this.stopAt=this.scrollUntil["offset"+this.position];
		var spaceRemains=this.object["scroll"+this.dimension] - this.scrollUntil["offset"+this.position];
			if(spaceRemains < this.object["client"+this.dimension]){
			this.stopAt-=this.object["client"+this.dimension] - spaceRemains;
			};
		}
		else if( document.getElementById(this.scrollUntil) ){
		var layerPos=document.getElementById(this.scrollUntil)["offset"+this.position];
		this.stopAt=layerPos;
		var spaceRemains=this.object["scroll"+this.dimension] - layerPos;
			if(spaceRemains < this.object["client"+this.dimension]){
			this.stopAt-=this.object["client"+this.dimension] - spaceRemains;
			};
		}
		else if( !isNaN(parseFloat(this.scrollUntil)) ){
		this.stopAt=Math.abs( (parseFloat(this.scrollUntil)||0) );/*abs: negative numbers may stall the timeout*/
		var spaceRemains=this.object["scroll"+this.dimension] - this.stopAt;
			if(spaceRemains < this.object["client"+this.dimension]){
			this.stopAt-=this.object["client"+this.dimension] - spaceRemains;
			};
		}
		else{/*no object argument: this.object defaults to the body tag, namely end of document*/
		this.stopAt=this.object["scroll"+this.dimension] - this.object["client"+this.dimension];
		};
		//RUN:
		if(this.object[this.scrollHow]<=this.stopAt){/*scroll to bottom or to right*/
		this.timer=setInterval(variableName+".scroll1()", this.speed);
		}
		else{/*scroll to top or to left*/
		this.timer=setInterval(variableName+".scroll2()", this.speed);
		};
	}
	/***** METHOD private *****/
	this.scroll1=function(){
	var toend=this.object[this.scrollHow] + this.amount;
		if(toend>=this.stopAt){ this.object[this.scrollHow]=this.stopAt; clearInterval(this.timer); this.timer=0; }
		else{ this.object[this.scrollHow]=toend; };
	}
	/***** METHOD private *****/
	this.scroll2=function(){
	var toend= this.object[this.scrollHow] - this.amount;
		if(toend<=this.stopAt){ this.object[this.scrollHow]=this.stopAt; clearInterval(this.timer); this.timer=0;}
		else{ this.object[this.scrollHow]=toend; };
	}
	/***** METHOD *****/
	this.scroll=function(){
		if(this.object/*exists*/ && !this.timer/*not running*/){
			this.afterLoad();
		}; 
	}
	/*class ends*//* keep this comment to reuse freely:
	http://www.unitedscripters.com */
}