Custom Facebook Connect Image

One of the ways you can put facebook connect button on your site is to use <fb:login-button> fbml tag something like this:

  <fb:login-button onlogin="window.location='www.example.com'"></fb:login-button>

That will show default facebook button with a rather small image. You can make the button little larger by specifying length and size attributes like this:

  <fb:login-button onlogin="window.location='www.example.com'" length="long" size="large"></fb:login-button>

However, the requirement in my case was that the button should be even bigger. I searched through the facebook connect docs and elsewhere but did not find a way to customize the facebook connect image (it is rendered directly by facebook; let me know if there is a way via comments please). I thought why I can’t force the facebook connect button to use the image that I specify. I fired up firebug (the addon of firefox) and this is what it showed for the <fb:login-button> fbml tag:

As can be seen, facebook automatically applies FB_login_button class amongst others to the connect button. As you can see, there is an img tag inside, that was all I needed to get my own image for the connect button. The idea is to find the image inside connect button and replace with your own once DOM has loaded. Now you get the idea, I wrote this jQuery code to get custom image for the connect button:

<script type="text/javascript">
$(function(){
  // overwrite the fb connect image - let's force it !!
  $('.FB_login_button').find('img').attr('src', 'img/my-custom-image.png');
});
</script>

We use the selector .FB_login_button and then use find method to find the image inside element (<fb:login-button>) having that class and replace its src attribute with the path of our custom image.  Since we have wrapped our code in ready handler $(function(){…}), our code will execute as soon as DOM becomes ready and when you visit the page, it will have your own custom facebook connect button image.

I also noticed that there was a link tag generated with the class of fbconnect_login_button. We could use that just as well like this:

<script type="text/javascript">
$(function(){
  // overwrite the fb connect image - let's force it !!
  $('.fbconnect_login_button').find('img').attr('src', 'img/my-custom-image.png');
});
</script>

Now this is good as long as you are using jQuery on the page where facebook connect button exists. But if you are not using jQuery, you can do the same thing with vanilla javascript albeit with little more code. Here is how you can do the same thing with vanilla javascript:

<script type="text/javascript">
window.onload = function(){
  var ourImg = null; // this will store the facebook connect img tag

  // find all the links on the current page
  var links = document.getElementsByTagName('a');

  // loop over all the links
  for(var i = 0; i < links.length; i++){
    // get class of this link
    var cls = links[i].className;

    // check to see if this is the link with specified class
    if (cls === 'fbconnect_login_button'){
      ourImg = links[i].firstChild; // which is img tag we need
      break;  // done, let's get the hell out of here
    }
  }

  // finally replace with our own image !
  ourImg.src = '<?php echo base_url() ?>images/fb.png';
};
</script>

Ops ! that is a lot of code I have written compared to jQuery’s but that’s what you need if you are not using jQuery on your page. Note that this time, we are using load event of the window window.onload = function(){…} which will fire when all the page resources are loaded including images, frames and the DOM unlike ready handler of jQuery which fires as soon as DOM becomes ready and runs before images, frames or any other external resources loaded into the page.

Finally, this is the page that now uses custom facebook connect button image while using <fb:login-button> fbml tag:

View the Page

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