• Passionate Developer

    HI David Thank you very much for such a nice tutorial … i am facing on issue with real time data base…im getting below error..
    FIREBASE WARNING: Exception was thrown by user callback. TypeError: Cannot read property 'replace' of undefined
    at nh.h.Mc (https://www.gstatic.com/firebasejs/3.3.2/firebase.js:434:247)
    at ef (https://www.gstatic.com/firebasejs/3.3.2/firebase.js:337:303)
    at Rb.te (https://www.gstatic.com/firebasejs/3.3.2/firebase.js:333:203)
    at https://www.gstatic.com/firebasejs/3.3.2/firebase.js:269:2159
    at Ub (https://www.gstatic.com/firebasejs/3.3.2/firebase.js:284:165)
    at Tb (https://www.gstatic.com/firebasejs/3.3.2/firebase.js:269:2143)
    at https://www.gstatic.com/firebasejs/3.3.2/firebase.js:322:1
    at pRTLPCB (https://s-usc1c-nss-113.firebaseio.com/.lp?start=t&ser=84593417&cb=1&v=5&ns=ehms-a6d34:6:55)
    at https://s-usc1c-nss-113.firebaseio.com/.lp?start=t&ser=84593417&cb=1&v=5&ns=ehms-a6d34:9:1
    firebase.js:434 Uncaught TypeError: Cannot read property 'replace' of undefined

    Can you help me in this!
    Thank you.

  • Jean Carlo De Castro

    The callback function of the on method is not firing, can someone help me with this? What im i doing wrong? CODE BELOW

    <!– FIREBASE –>
    <script src="https://www.gstatic.com/firebasejs/3.4.0/firebase.js"></script>
    // Initialize Firebase

    const dbRefObject = firebase.database().ref().child('object');

    dbRefObject.on('value', function (snap) {

  • Filipe Tavares

    Does anyone know how to get started with firebase on ionic? I'm curious because I'm creating an app and I need to connect it with firebase!

  • Faniry devs

    #AskFirebase hi David, you rock. Let's say I use Phantomjs to inject Firebase 3 into webpages for web scraping. How do I push a json object from there into the realtime database? This one is a bonus : why don't you use Firebase for Youtube comments? Peace!

  • Rinzler

    I am needing to synchronize user inputted, personal user data which should stay specific to that user and that user only. Just to be sure, I should use database rules to set that up correct?

    Also, Is there a way I can organize and serve that users data to them in different ways? So, for example I'd like to give the user the ability to sort through their data items by name or by common color (common item value? grouping by common value?) Is that something that I can do through Firebase by any chance?

  • Harvy Kevin Cuyno

    hi, i have this proj where i need a data from my computer to be send to the firebase database automatically, is it possible to create such program using c# or c++ thankss..

  • Alwin Jolliffe

    I'm making an app that needs to display the same content a.s. the website. Can I use firebase to synchronise the website data with the app in realtime?? I'm hoping that you have a video covering this issue.

  • Empório do Monge - Cervejas e Presentes

    Hi. Congratulations ! I'm not sure if I'm doing the right thing, but using the script from the previous video (below)
    <!DOCTYPE html>
    <meta charset="utf-8">
    <title>Firebase Quick Start</title>

    <h1 id="bigOne"></h1>

    <script src="https://www.gstatic.com/firebasejs/3.6.4/firebase.js"></script>
    // Initialize Firebase
    var config = {
    apiKey: "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
    authDomain: "xxxxxx.firebaseapp.com",
    databaseURL: "https://xxxxxx.firebaseio.com",
    storageBucket: "xxxx.appspot.com",
    messagingSenderId: "99999999999"

    var bigOne = document.getElementById('bigOne');
    var dbRef = firebase.database().ref().child("object");
    dbRef.on('value', snap => bigOne.innerText = snap.val());


    it's working good.

    But using the current script I have nothing from firebase. may you help me ?

  • swami nathan

    Hi , i am new in firebase , i have red your documents and i am using angularfire

    i have a firebase database and i have three object such as country , city and state now i want filter city depends on country .

    i have factory in angular module and i have function getcitybycountryid and passed country and i have used code like this


    i got result with object and i don't know how to return result via factory function

    please give me the solution as soon as possible.


  • omkar joshi

    hi, can we access firebase database without any listener, because i building an android app which requires a product database which will not be updated every time, so how can i access that data.

  • Marvin Quiñónez

    Help please! I have the message Uncaught ReferenceError: firebase is not defined!! I have the same code!

  • Rushabh Oswal

    I have an hybrid app that works on iOS and Android, can I make 1 firebase databse common,so I can synchronise between them?

  • Tech Tip's Trick's And Hack's

    Great Post
    Thanks a lot it helped me a lot
    I am also going to share it to my friends and over my social media.
    Hackr.io is a great platform to find and share the best tutorials and they have a specific page for Firebase

    This might be useful to your readers: https://hackr.io/tutorials/learn-firebase

  • Jamie Anderson

    No matter what I do, I cannot view anything in my browser's console and I'm using chrome. It works for text but not for console logs.

  • steven Gao

    How to remove observer in tableview? I mean everytime a cell is deque or move out the view when scroll down, how can i remove the observer, because if i scroll down 3 times everytime i tap "like", button, it get called three times, please help, google search long time, and no results

  • Moin Javaid

    hi.I just want to make a web app and android app using firebase. what i upload in web app it should shown on android app any can help me how can i do that.


    hello I love the ease of firebase functions, but I would like to be able to program anywhere I am and I have not found how to do it. They should have how to do this from an APP, or from the web. thus nothing would program the code, I give it to save and it should be published. Thank you

  • Adel Jojo

    Its clear that Web hosting is for uploading my app to the cloud. But what I am gonna use this firebase realtime database for in a real world app?

  • Rajani Salvi

    hi David , great video can you help me for how i can take request of android app in api with php and response . with firebase realtime database. there is may be multiple request at a time and send mutiple respose form one . please guide me.

  • Developers Company

    hi can you tell how to send push notification for mobilr apps not through firebase console but from client app….plz reply me

  • rick-des

    1) How are you using the "localhost:5000"? Were you using FireBase CLI and the $serve command in cmd, some other Google/FireBase feature, or was it some 3rd party source unlreated to Firebase/Google?
    2) In order to view the changes in the DB in the html, is it necessary to be running on a web server, or do you merely need to open the html in a browser with the Firebase code in a <script> tag (i.e. "var config={…}" and the other stuff)?
    3) If I wanted to incorporate FireBase into a WebView Android app, should I use the configuration (and guides) for Android deplayment or for Web?

    I have been trying to work with FireBase for a week, with little to no luck.

  • SAI KRISHNA krishna

    how he got localhost :5000 in web browser. HE havent gave any explanation.
    That is where i got struck. please help me

  • Axiom Drive

    Wait it's not printing anything welp, my code:
    (function() {

    // Initialize Firebase
    var config = {
    This is so that u guys dont steal my app data

    // Get elements
    const preObject = document.getElementById("object");

    // Create references
    const dbRefObject = firebase.database().ref().child("object");

    // Sync object changes
    dbRefObject.on("value", snap => console.log(snap.val()));


  • Arled Ko

    I want to do a simple login screen without using authentication? Have my own table of users where where the login is simple their name and postcode

  • Banting Gamer

    if you use const dbRefObject = firebase.database().ref("object/favNumber"); will you get the reference only to the favNumber? i want to know if the entire object (object) is returned across the web or just the value of favNumber?

    in my chat app im thinking of using the realtime database to store my user profile information like username and user profile image ect. And then for my chat messages using cloud firestore. im trying to figure out the most cost effective way to load profile images in group chats.

  • adrian najera

    this error keeps occurring and I don't know why: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client I am using express and firebase-admin

  • Paul P

    I'd like to see a SIMPLE (till now I only sow complicated, awkward!) way to do it the other way around: updating a site variable to be persisted in firebase

  • rmzzz76

    Watching in 2019. Doesn't work. Nor do the other web examples. Using the CDN to reference the firebase libraries, libraries load just fine however providing config data (which I'm 100% certain is valid config data because it was generated in Firebase console), white listed domains but still get "Uncaught ReferenceError: firebase is not defined" JavaScript error when trying to get the database reference. From searching looks like I'm not the only one… Amazing how a great product can turn to absolutely useless garbage with a problem like this. At this point have lost so much time trying various solutions (changing to previous versions of library, stripping things down to a verbatim copy of what the examples provide… STILL DOES NOT WORK. I see this as a failure on the part of the entire team. Time to move on to another option.

  • Deepanshu Gautam

    Hello all,can someone helpme out as fast as u can.

    Im facing an issuing on pushing the data to firebase …it isnt updating the database but the alert box that is written inside the submitButton(){} is working .Thank you in advance

  • joaquim paul

    hey, David having an issue here while trying to run my null index.html it throws this error in the console "firebase.database is not a function any help, please?

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