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;

                    }

            }