How to change facebook login button with my custom image

Found a site on google explaining some changes, according to the author of the page fb does not allow custom buttons. Heres the website.

Unfortunately, it’s against Facebook’s developer policies, which state:

You must not circumvent our intended limitations on core Facebook features.

The Facebook Connect button is intended to be rendered in FBML, which means it’s only meant to look the way Facebook lets it.

The method which you are using is rendering login button from the Facebook Javascript code. However, you can write your own Javascript code function to mimic the functionality. Here is how to do it -

1. Create a simple anchor tag link with the image you want to show. Have a onclick method on anchor tag which would actually do the real job.

<a href="#" onclick="fb_login();"><img src="images/fb_login_awesome.jpg" border="0" alt=""></a>

2. Next, we create the Javascript function which will show the actual popup and will fetch the complete user information, if user allows. We also handle the scenario if user disallows our facebook app.

window.fbAsyncInit = function() {
    FB.init({
        appId   : 'YOUR_APP_ID',
        oauth   : true,
        status  : true, // check login status
        cookie  : true, // enable cookies to allow the server to access the session
        xfbml   : true // parse XFBML
    });

  };

function fb_login(){
    FB.login(function(response) {

        if (response.authResponse) {
            console.log('Welcome!  Fetching your information.... ');
            //console.log(response); // dump complete info
            access_token = response.authResponse.accessToken; //get access token
            user_id = response.authResponse.userID; //get FB UID

            FB.api('/me', function(response) {
                user_email = response.email; //get user email
          // you can store this data into your database             
            });

        } else {
            //user hit cancel button
            console.log('User cancelled login or did not fully authorize.');

        }
    }, {
        scope: 'public_profile,email'
    });
}
(function() {
    var e = document.createElement('script');
    e.src = document.location.protocol + '//connect.facebook.net/en_US/all.js';
    e.async = true;
    document.getElementById('fb-root').appendChild(e);
}());

3. We are done.

Please note that the above function is fully tested and works. You just need to put your facebook APP ID and it will work.

I got it working with a call to something as simple as

function fb_login() {
  FB.login( function() {}, { scope: 'email,public_profile' } );
}

I don't know if facebook will ever be able to block this circumvention, but for now I can use whatever HTML or image I want to call fb_login and it works fine.

Reference: Facebook API Docs

It is actually possible only using CSS, however, the image you use to replace must be the same size as the original facebook log in button. Fortunately Facebook delivers the button in different sizes.

From facebook:

size - Different sized buttons: small, medium, large, xlarge - the default is medium. https://developers.facebook.com/docs/reference/plugins/login/

Set the login iframe opacity to 0 and show a background image in the parent div

.fb_iframe_widget iframe {
    opacity: 0;
}

.fb_iframe_widget {
  background-image: url(another-button.png);
  background-repeat: no-repeat; 
}

If you use an image that is bigger than the original facebook button, the part of the image that is outside the width and height of the original button will not be clickable.