麻烦帮忙看看哪里错了,求的数值显示不出来,显示的日期也有问题QAQ
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<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>系好安全带,准备启航</title>
<script type="text/javascript">
var mydate=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(mydate.getFullYear()+"年"+(mydate.getMonth()+1)+"月"+mydate.getDay()+"日"+" "+weekday[mydate.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 myarr=scoreStr.split(";");
var sum=0;
for(var i=0,i<myarr.length,i++){
var score=parseInt(myarr[i].substring("3,5"));
sum+=score;
}
document.write("——班级总分为:"+sum);
document.write(" 班级平均分为:"+Math.round(sum/myarr.length));
</script>
</head>
<body>
</body>
</html>