function imgadapter(obj,width,height)
{
//alert('缩放前');
	var max_height = height-6;    //减去图片外加的边框和Pdding值
	var max_width = width-6;      
	var real_height = obj.height;
	var real_width = obj.width;
	var img_pdding;
	
	//产品图片按比例缩放
	if(obj.height>max_height)
	{
		obj.height = max_height;
		obj.width = Math.round(obj.height*(real_width/real_height));
	}
	if(obj.width>max_width)
	{
		obj.width = max_width;
		obj.height = Math.round(obj.width*(real_height/real_width));
	}
	
	//产品图片上下居中---(1)没有按比例缩放时,图片的实际高度小于传入参数width.  (2)按比例缩放后,图片的高度小于传入参数
	if(obj.height<max_height)
	{
		img_padding = Math.round((max_height-obj.height)/2);
		obj.style.paddingTop=img_padding;
		obj.style.paddingBottom=img_padding;
	}
	
	//产品图片左右居中
	if(obj.width<max_width)
	{
		img_padding = Math.round((max_width-obj.width)/2);
		obj.style.paddingLeft=img_padding;
		obj.style.paddingRight=img_padding;
	}
	
obj.style.visibility ='visible' ;
//alert('缩放后');
}