Authenticate with Facebook Button

facebook-button-function.php

 public function authenticate_with_facebook() {
    	?>
			<p><a href="#" onClick="logInWithFacebook()">Log In with the JavaScript SDK</a></p>
			<script>
			  logInWithFacebook = function() {
			    FB.login(function(response) {
			      if (response.authResponse) {
			        //alert('You are logged in &amp; cookie set!');
			        // Now you can redirect the user or do an AJAX request to
			        // a PHP script that grabs the signed request from the cookie.
			        jQuery.ajax({
				        url: '<?php echo plugin_dir_url(__FILE__); ?>facebook-js-login.php',
				        type: 'POST',
				        data: {
				            app_id: "<?php echo get_option('facebook_app_id'); ?>",
				            app_secret: "<?php echo get_option('facebook_app_secret'); ?>"
				        }
				    }).done(function(data){
				        //alert(JSON.stringify(data));
				    });

			      } else {
			        //alert('User cancelled login or did not fully authorize.');
			      }
			    }, {scope: 'public_profile, email, user_likes, user_photos, user_posts, user_events'});
			    return false;
			  };
			  window.fbAsyncInit = function() {
			    FB.init({
			      appId: <?php echo get_option('facebook_app_id'); ?>,
			      cookie: true, // This is important, it's not enabled by default
			      version: 'v2.2'
			    });
			  };

			  (function(d, s, id){
			    var js, fjs = d.getElementsByTagName(s)[0];
			    if (d.getElementById(id)) {return;}
			    js = d.createElement(s); js.id = id;
			    js.src = "//connect.facebook.net/en_US/sdk.js";
			    fjs.parentNode.insertBefore(js, fjs);
			  }(document, 'script', 'facebook-jssdk'));
			</script>
    	<?php
    }