JavaScript ---案例（统计字符出现次数）
统计字符出现次数
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
</head>
<body><script>var str = "abcabcabbbbbbbbbbbb"var obj = {}for(var i=0;i<str.length;i++){console.log(str[i])var key = str[i]if(obj[key]){obj[key]++}else{obj[key] = 1}}console.log(obj)</script>
</body>
</html>