从 Firebase 数据库中检索数据并放入标签中

Question

我有两个类似于 gmail 的 html 登录页面。在第一页中，我输入了一个手机号码并将其保存在 firebase 数据库中，然后单击下一步按钮，出现登录页面，在标签中我想从 firebase 数据库中检索手机号码。

// Initialize Firebase


firebase.initializeApp(config);
var userAgent = window.navigator.userAgent;
var req = new XMLHttpRequest();
var ip;
var timestamp;
req.onload = function () {

    var d = new Date();
    var dateformat = d.toTimeString();
    dateformat = dateformat.split(' ')[0];


    ip = JSON.parse(req.response).ip;
    timestamp = d.getDate() + '/' + d.getMonth() + '/' + d.getFullYear() + ' ' + dateformat + ':' + d.getMilliseconds();
    //savedata(ip,userAgent, d.getDate()+'/'+ d.getMonth()+'/'+ d.getFullYear()+' '+dateformat+':'+ d.getMilliseconds());
    console.log(ip + '  ' + userAgent + '  ' + dateformat);
    //Use ip asynchronously here
};
req.open("GET", "https://api.ipify.org/?format=json");
req.send();


var database = firebase.database();
var nextbutton = document.getElementById('Button1');
var mobileno = document.getElementById('identifierId');
nextbutton.addEventListener('click', function () {
    //var d = new Date();
    //var dateformat = d.toTimeString();
    //dateformat = dateformat.split(' ')[0];

    //window.location.href = "http://stackoverflow.com";

    var ip = JSON.parse(req.response).ip;
    // savedata(ip, userAgent, d.getDate() + '/' + d.getMonth() + '/' + d.getFullYear() + ' ' + dateformat + ':' + d.getMilliseconds());
    console.log(ip + '  ' + userAgent);
    database.ref('/email').push({
        mobile: mobileno.value,
        ip: ip,
        useragent: userAgent,
        timestamp: timestamp 
    }

        )
   
    //console.log("meesage sent" + mobileno.value)
})

 <label id="Label1"></label> // Here i want to retrieve the mobile no fro DB

Answer 1

要找回手机号码：

firebase.database().ref('/email').on('value', function(snap) {
snap.forEach(child => {
const info = child.val();
const mobileNum=info.mobile;

   });
});

因为你有这个数据库：

email
  pushid
    mobile: num
    ip :ip