/*案例图片切换*/
function addloadevent(func) {
	var oldonload = window.onload;
	if (typeof window.onload != 'function') {
		
	} else {
		window.onload = function() {
			oldonload();
			func();
		}
	}
}
function focus() {
	function byid(id) {
		return document.getelementbyid(id);
	}
	function bytag(tag, obj) {
		return (typeof obj == 'object' ? obj: byid(obj)).getelementsbytagname(tag);
	}
	var timer = null;
	var ofocus = byid('tfocus');
	var opic = byid('tfocus-pic');
	var opiclis = bytag('li', opic);
	var obtn = byid('tfocus-btn');
	var obtnlis = bytag('li', obtn);
	var iactive = 0;
	function inlize() {
		opiclis[0].style.filter = 'alpha(opacity:100)';
		opiclis[0].style.opacity = 100;
		opiclis[0].style.zindex = 5;
	};
	for (var i = 0; i < opiclis.length; i++) {
		obtnlis[i].sindex = i;
		obtnlis[i].onclick = function() {
			if (this.sindex == iactive) return;
			iactive = this.sindex;
			changepic();
		}
	};
	byid('tfocus-leftbtn').onclick = byid('prev').onclick = function() {
		iactive--;
		if (iactive == -1) {
			iactive = opiclis.length - 1;
		}
		changepic();
	};
	byid('tfocus-rightbtn').onclick = byid('next').onclick = function() {
		iactive++;
		if (iactive == opiclis.length) {
			iactive = 0;
		}
		changepic();
	};
	
	function changepic() {
		for (var i = 0; i < opiclis.length; i++) {
			domove(opiclis[i], 'opacity', 0);
			opiclis[i].style.zindex = 0;
			obtnlis[i].classname = '';
		};
		domove(opiclis[iactive], 'opacity', 100);
		opiclis[iactive].style.zindex = 5;
		obtnlis[iactive].classname = 'active';
		if (iactive == 0) {
			domove(bytag('ul', obtn)[0], 'left', 0);
		} else if (iactive >= opiclis.length - 2) {
			domove(bytag('ul', obtn)[0], 'left', -(opiclis.length - 3) * (obtnlis[0].offsetwidth + 4));
		} else {
			domove(bytag('ul', obtn)[0], 'left', -(iactive - 1) * (obtnlis[0].offsetwidth + 4));
		}
	};
	function autoplay() {
		if (iactive >= opiclis.length - 1) {
			iactive = 0;
		} else {
			iactive++;
		}
		changepic();
	};
	atimer = setinterval(autoplay, 2000);
	inlize();
	function getstyle(obj, attr) {
		if (obj.currentstyle) {
			return obj.currentstyle[attr];
		} else {
			return getcomputedstyle(obj, false)[attr];
		}
	};
	function domove(obj, attr, itarget) {
		clearinterval(obj.timer);
		obj.timer = setinterval(function() {
			var icur = 0;
			if (attr == 'opacity') {
				icur = parseint(parsefloat(getstyle(obj, attr)) * 100);
			} else {
				icur = parseint(getstyle(obj, attr));
			}
			var ispeed = (itarget - icur) / 6;
			ispeed = ispeed > 0 ? math.ceil(ispeed) : math.floor(ispeed);
			if (icur == itarget) {
				clearinterval(obj.timer);
			} else {
				if (attr == 'opacity') {
					obj.style.filter = 'alpha(opacity:' + (icur + ispeed) + ')';
					obj.style.opacity = (icur + ispeed) / 100;
				} else {
					obj.style[attr] = icur + ispeed + 'px';
				}
			}
		},
		30)
	};
	byid('tfocus').onmouseover = function() {
		clearinterval(atimer);
	}
	byid('tfocus').onmouseout = function() {
		atimer = setinterval(autoplay, 3000);
	}
}