這代碼有啥問題嗎，為啥23行老是報錯呢

function?arr(obj,json,fn){
	var?flag=true??//
	clearInterval(obj.timer);
	obj.timer=setInterval(function(){
		for(var?attr?in?json){
			var?icun=0;
		//判斷是opacity就parseflaot（取浮點數），parseInt
		if(attr=='opacity'){
			icun=Math.round(parseFloat(getstyle(obj,attr))*100)
		}else{
			icun=parseInt(getstyle(obj,attr));
		}
		//設置速度
		var?speed=(json[attr]-icun)/20;
		speed=speed>0?Math.ceil(speed):Math.floor(speed);
		if(json[attr]!=icun){
			flag=false
		}
			if('opacity'){
				li.style[attr]=(icun+speed)/100;
			}
			li.style[attr]=icun+speed+'px';
			
		if(flag){
			clearInterval(obj.timer);
			if(fn){
				fn();
			}
		}
		}
	},20);
}