<!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>统计字符串个数</title>
</head>
<body>
<script >
function countNumber(str) {
var sum = 0; //计数变量
var arr = str.split('')
for ( i = 0 ; i < arr.length; i++ ){ //遍历数组
sum++;//自加
}
console.log(sum)
}
var oldStr = countNumber('Rome was not built in a day');
</script>
</body>
</html>