总分为NaN班级平均分为NaN 求大神指教
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" Content="text/html; charset=utf-8" />
<title> 平均分</title>
<script type="text/javascript">
var mydate=new Date();
document.write(mydate.getFullYear()+"年"+(mydate.getMonth()+1)+"月"+mydate.getDate()+"日");
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(" " +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 scoreArr=scoreStr.split(";");
var sum=0;
for (var i = 0;i<scoreArr.length; i++) {
var index = scoreArr[i].indexOf(":");
sum += parseInt( scoreArr[i].substr(index+1,2) );
}
av = sum/scoreArr.length;
av = Math.floor(av);
document.write("班级总分为" + sum );
document.write("班级平均分为" + av );
</script>
</head>
<body>
</body>
</html>
