参考: https://www.cnblogs.com/hello321/p/7821400.html
 
function countLength(str) {
        var inputLength = 0;
        //给一个变量来记录长度
        for (var i = 0; i < str.length; i++) {
            var countCode = str.charCodeAt(i);
            console.log("countCode打印:",countCode);
            //返回指定位置的字符的Unicode编码
            //判断是不是ASCII码,Unicode码前128个字符是ASCII码
            if (countCode >= 0 && countCode <= 128) {
                inputLength++;
            } else {
                inputLength += 2;
                //如果是扩展码,则一次+2
            }
        }
        return inputLength;
    }
    console.log(countLength(",.?!@ a bczAZ喊,。?!"));