为什么total要先赋值为0？
不能只声明吗？我原先写的是“var total;”，这样有什么问题呢？
<!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">
//通过javascript的日期对象来得到当前的日期，并输出。
var mydate = new Date();
var year = mydate.getFullYear();
var month = mydate.getMonth();
var date = mydate.getDate();
var day = mydate.getDay();
var weekdays = ["日","一","二","三","四","五","六"];
document.write(year+"年"+month+"月"+day+"日"+" "+"星期"+weekdays[day]);
//成绩是一长窜的字符串不好处理，找规律后分割放到数组里更好操作哦
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 individuals = scoreStr.split(";");
var total = 0;
for (i=0;i<individuals.length;i++){
var score = individuals[i].slice(-2);
total += parseInt(score);
}
var average = Math.floor(total/individuals.length);
document.write("--班级总分为:"+average);
//从数组中将成绩撮出来，然后求和取整，并输出。
</script>
</head>
<body>
</body>
</html>
