function imgResize(img)
{
	var maxWidth=650;
	var scale=img.height/img.width;
	if(img.width>maxWidth)
	{
		img.width=maxWidth;
		img.height=maxWidth*scale;
	}
	img.style.cursor= "pointer"; //改变鼠标指针 
	img.onclick = function() { window.open(this.src);} //点击打开大图片 
	if (navigator.userAgent.toLowerCase().indexOf("ie") > -1)
	{ //判断浏览器，如果是IE 
	   img.title = "请使用鼠标滚轮缩放图片，点击图片可在新窗口打开"; 
	   img.onmousewheel = function img_zoom() //滚轮缩放 
		{ 
			var zoom = parseInt(this.style.zoom, 10) || 100; 
			zoom += event.wheelDelta / 12; 
			if (zoom> 0)　this.style.zoom = zoom + "%"; 
			return false; 
		} 
	}
	else
	{ //如果不是IE 
	   img.title = "点击图片可在新窗口打开"; 
	} 
}