正则表达式：手机号隐藏中间四位，身份证隐藏位数

return  (obj).replace(/(\d{3})\d{4}(\d{4})/, '$1****$2');

return  (obj).replace(/(\w)/g,function(a,b,c,d){return ((c>1&&c<6)||c>(obj.length-5))?'*':a});;