You can do it in JavaScript like so (Building off of @dwarfy's response to a similar question):
<html>
<head>
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<style type="text/css">
div#container_notlike, div#container_like {
display: none;
}
</style>
</head>
<body>
<div id="fb-root"></div>
<script>
window.fbAsyncInit = function() {
FB.init({
appId : 'YOUR_APP_ID', // App ID
channelUrl : 'http(s)://YOUR_APP_DOMAIN/channel.html', // Channel File
status : true, // check login status
cookie : true, // enable cookies to allow the server to access the session
xfbml : true // parse XFBML
});
FB.getLoginStatus(function(response) {
var page_id = "YOUR_PAGE_ID";
if (response && response.authResponse) {
var user_id = response.authResponse.userID;
var fql_query = "SELECT uid FROM page_fan WHERE page_id = "+page_id+"and uid="+user_id;
FB.Data.query(fql_query).wait(function(rows) {
if (rows.length == 1 && rows[0].uid == user_id) {
console.log("LIKE");
$('#container_like').show();
} else {
console.log("NO LIKEY");
$('#container_notlike').show();
}
});
} else {
FB.login(function(response) {
if (response && response.authResponse) {
var user_id = response.authResponse.userID;
var fql_query = "SELECT uid FROM page_fan WHERE page_id = "+page_id+"and uid="+user_id;
FB.Data.query(fql_query).wait(function(rows) {
if (rows.length == 1 && rows[0].uid == user_id) {
console.log("LIKE");
$('#container_like').show();
} else {
console.log("NO LIKEY");
$('#container_notlike').show();
}
});
} else {
console.log("NO LIKEY");
$('#container_notlike').show();
}
}, {scope: 'user_likes'});
}
});
};
// Load the SDK Asynchronously
(function(d){
var js, id = 'facebook-jssdk'; if (d.getElementById(id)) {return;}
js = d.createElement('script'); js.id = id; js.async = true;
js.src = "//connect.facebook.net/en_US/all.js";
d.getElementsByTagName('head')[0].appendChild(js);
}(document));
</script>
<div id="container_notlike">
YOU DON'T LIKE ME :(
</div>
<div id="container_like">
YOU LIKE ME :)
</div>
</body>
</html>
Where the channel.html file on your server just contains the line:
<script src="//connect.facebook.net/en_US/all.js"></script>
There is a little code duplication in there, but you get the idea. This will pop up a login dialog the first time the user visits the page (which isn't exactly ideal, but works). On subsequent visits nothing should pop up though.