求高手解答，急

源自：7-23 编程练习

<title>系好安全带,准备启航</title>

var myday = new Date();

var weekday = ["星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"];

document.write(myday.getFullYear() + "年" + myday.getMonth() + "月" + myday.getDate() + "日"+weekday[myday.getDay()]);

var scoreStr = "小明:87;小花:81;小红:97;小天:76;小张:74;小小:94;小西:90;小伍:76;小迪:64;小曼:76";

var all=scoreStr.split(";");

var sum=0;

for (var i = 0; i < all.length; i ++) {

sum += parseInt(all[i].substr(all[i].indexOf(":")+1));

//document.write("<br>" + sum);//test

}

document.write(sum+"</br>");

document.write(all.length+"</br>")

document.write(Math.round(sum/all.length));

</script>

</head>

<body>

请教高手，为什么我最后哪里不加parseInt就没有结果了，明明是两个数字类型啊？help。

提问者：qq_听一半的歌_1 2017-05-13 01:48