js获取字符长度

 var len = 0;
            for (var i = 0; i < customerName.length; i++) {
                 var a = customerName.charAt(i);
                 if (a.match(/[^\x00-\xff]/ig) != null) {
                    len += 2;
                    }
                else{
                    len += 1;
                    }
            }