js手机格式校验+隐藏手机号中间四位，变成*星号 || 身份证生日四位变*

//手机号格式校验

if (/^1[3456789]\d{9}$/.test(phonenum)) { //判断手机号

      console.log(手机号正确);

}

//手机号中间四位用“ **** ”代替

var

tel = 

"13122223333"

;

var

reg = /^(\d{3})\d{4}(\d{4})$/;

tel = tel.replace(reg, 

"$1****$2"

);

console.log(tel);

//空格分隔手机号码

let phone = '88888888888'

let res = phone.replace(/^(.{3})(.*)(.{4})$/, '$1 $2 $3')

console.log(res) // 888 8888 8888

//js身份证中间四位（生日）变为*号

var str='13333319700902123X';

var str1=str.replace(/(\d{10})(\d+)(\d{3})/,function(x,y,z,p){

    var i="";

    while(i.length<z.length){i+="*"}

    return y+i+p

})

console.log(str1) 

//1333331970****123X