为什么什么都没有输出？
<!DOCTYPE HTML>
<html >
<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"]；
var mynum=mydate.getDay();
var year=mydate.getFullYear();
var month=mydate.getMonth();
var day=mydate.getDate();
document.write(year+"年"+month+"月"+day+"日"+weekday[mynum]);
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 personal=scoreStr.split(";");
var temp;
var sum=0;
var score=new Array();
for(var i=0;i<10;i++){
temp=personal[i].split(":");
}
var avg=sum/10
document.write("班级总分为："+sum "班级平均分为："+avg);
</script>
</head>
<body>
</body>
</html>
