/// clipHeight and scrollHeight are not recognized in Opera >> use fix numbers
function verifyCompatibleBrowser(){ 

	this.agt=navigator.userAgent.toLowerCase();
    this.ver=navigator.appVersion 
    this.dom=document.getElementById?1:0 
    this.ie5=(navigator.appName.indexOf("Microsoft") != -1 && this.dom)?1:0;
    this.ie4=(document.all && !this.dom)?1:0; 
    this.ns5=(this.dom && parseInt(this.ver) >= 5) ?1:0; 
    this.ns4=(document.layers && !this.dom)?1:0;
    this.opera = (this.agt.indexOf("opera")!= -1)?1:0;
    this.bw=(this.ie5 || this.ie4 || this.ns4 || this.ns5);
    return this;
} 
bw=new verifyCompatibleBrowser();
if(bw.bw==false) alert("attention!!!!\nplease shut down your computer.");
 
var speed=30;
var loop, timer;
 
function ConstructObject(obj,nest){ 
    nest=(!nest) ? '':'document.'+nest+'.'
    this.el=bw.dom?document.getElementById(obj):bw.ie4?document.all[obj]:bw.ns4?eval(nest+'document.'+obj):0; 
    this.css=bw.dom?document.getElementById(obj).style:bw.ie4?document.all[obj].style:bw.ns4?eval(nest+'document.'+obj):0;
    this.scrollHeight=bw.ns4?this.css.document.height:this.el.offsetHeight;
	//this.clipHeight=bw.ns4?this.css.clip.height:this.el.offsetHeight;
	if(bw.opera) {this.scrollHeight=856;}
	this.clipHeight=184;
    this.up=MoveAreaUp;
	this.down=MoveAreaDown; 
    this.MoveArea=MoveArea; this.x; this.y;
    this.obj = obj + "Object";
    eval(this.obj + "=this");
    return this;
} 
function MoveArea(x,y){
    this.x=x;this.y=y;
    this.css.left=this.x;
    this.css.top=this.y;
}
 
function MoveAreaDown(move){
	if(this.y>-this.scrollHeight+objContainer.clipHeight){
    this.MoveArea(0,this.y-move) 
    if(loop) {setTimeout(this.obj+".down("+move+")",speed);}
	} 
} 

function MoveAreaUp(move){
	if(this.y<0){ 
    this.MoveArea(0,this.y-move) 
    if(loop) setTimeout(this.obj+".up("+move+")",speed) 
	} 
} 
 
function PerformScroll(speed){
	if(initialised){
		loop=true;
		if(speed>0) {objScroller.down(speed);}
		else objScroller.up(speed);
	} 
} 
 
function CeaseScroll(){ 
    loop=false
    if(timer) clearTimeout(timer);
} 
var initialised;
function InitialiseScrollableArea(){ 
    objContainer=new ConstructObject('divContainer');
    objScroller=new ConstructObject('divContent','divContainer');
    objScroller.MoveArea(0,0);
    objContainer.css.visibility='visible';
    initialised=true;
}