function G(id){
	return document.getElementById(id);
}
var __n=0;
var sp=0.08;
var st = 0;
var tmp;
var timers=new Array();
var Links=[];
var Imgs =G('img').getElementsByTagName('a');
function slide(n){
	G('txt').innerHTML=Links[n].innerHTML;
	var btn=G('btn').getElementsByTagName('a');
	for(var i=0; i<btn.length; i++){
		if(i == n){
			btn[n].className = 'btna';
			Imgs[i].style.display="block";
			tmp=Imgs[i];
			st=0;		
			timers[1]=setInterval(doAlpha,10);
			continue;
		}
		btn[i].className = '';
		Imgs[i].style.display="none";
	}
}
function doAlpha(){
	st=st+sp*(100-st);
	SetAlpha(tmp,parseFloat(st).toFixed(0));
	if(parseFloat(st).toFixed(0)==100){
		if(timers[1]){clearInterval(timers[1])};
	}
}
function SetAlpha(oi,opacity){
	if(document.all){
		oi.style.filter = "alpha(opacity="+opacity+")";
	}else{
		oi.style.MozOpacity = opacity/100;
	}
}
var slideInit = function(){
	if(__n == 4) __n = 0;
	slide(__n);
	__n++;
}
window.onload=function(){
	window.Links =G('txtdata').getElementsByTagName('div');	
	slideInit();
	timers[0]=setInterval(slideInit, 5000);
	var btn=G('btn').getElementsByTagName('a');	
	for(var i=0; i<4; i++){
		btn[i].setAttribute("num",i);
		btn[i].onmouseover=function(){clearInterval(timers[0]);}
		btn[i].onclick=function(){if(timers[1]){clearInterval(timers[1])};__n=this.getAttribute("num");slide(__n);}		
		btn[i].onmouseout=function(){__n++;timers[0]=setInterval(slideInit, 5000);}
		btn[i].onfocus=function(){this.blur()}
	}	
}