手机号中间4位为*

var reg = /^(\d{3})(\d*)(\d{4})$/;

var str = " 15516236523";

str = str .replace(reg,function（a,b,c,d）{

return b + c.replace(\/d\g,"*") + d ;

console.log(str);

});

2019-10-08:10:40