我用for后，怎么將數(shù)字提出來計(jì)算和跟平均值？
<!DOCTYPE? HTML>
<html >
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>系好安全帶,準(zhǔn)備啟航</title>
<script type="text/javascript">
? //通過javascript的日期對象來得到當(dāng)前的日期，并輸出
? ? var sj = new Date();
? ? var nian = sj.getYear();??
? ? var yue = sj.getMonth();
? ? var ri = sj.getDate();
? ? var weekday=["星期日","星期一","星期二","星期三","星期四","星期五","星期六"];
? ? var xq = sj.getDay();
? ? var xqj = weekday[xq];
? ? document.write(nian+"年"+yue+"月"+ri+"日"+"? "+xqj);
??
? //成績是一長竄的字符串不好處理，找規(guī)律后分割放到數(shù)組里更好操作哦
? ? var scoreStr = "小明:87;小花:81;小紅:97;小天:76;小張:74;小小:94;小西:90;小伍:76;小迪:64;小曼:76";
? ? for(var i=3;i<=scoreStr.length;i=i+6){
? ? document.write(scoreStr.substr(i,3));
? ? }
? ??
? ??
? //從數(shù)組中將成績撮出來，然后求和取整，并輸出。
</script>
</head>
<body>
</body>
</html>
2018-07-11
<!DOCTYPE? HTML>
<html >
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>系好安全帶,準(zhǔn)備啟航</title>
<script type="text/javascript">
? //通過javascript的日期對象來得到當(dāng)前的日期，并輸出
??? var sj = new Date();
??? var nian = sj.getYear();?
??? var yue = sj.getMonth();
??? var ri = sj.getDate();
??? var weekday=["星期日","星期一","星期二","星期三","星期四","星期五","星期六"];
??? var xq = sj.getDay();
??? var xqj = weekday[xq];
??? document.write(nian+"年"+yue+"月"+ri+"日"+"? "+xqj);
?
? //成績是一長竄的字符串不好處理，找規(guī)律后分割放到數(shù)組里更好操作哦
??? var scoreStr = "小明:87;小花:81;小紅:97;小天:76;小張:74;小小:94;小西:90;小伍:76;小迪:64;小曼:76";
??? var newArr=new Array();
??? var j=0;
??? newArr=scoreStr.split(';');
??? for(var i=0;i<newArr.length;i++){
?????? newArr[i] = newArr[i].substring(3);
?????? document.write(newArr[i]+'<br/>');
??? }
? //從數(shù)組中將成績撮出來，然后求和取整，并輸出。
???? j=1;
???? for(var k=0;k<newArr.length;k++){
????????? newArr[k]=Math.parseInt(newArr[k]);
???????? j=j+newArr[k];
???? }
???? document.write(j);
</script>
</head>
<body>
</body>
</html>
2018-07-11
j的值是0
2018-07-11
把新取出來的數(shù)存放到一個(gè)新的數(shù)組中,等下要操作直接遍歷