Retrieve facebook post URL with post_id - facebook

Question

I want to get URL of users who share from my links, I have got the post_id but when I try to get full post URL, facebook asking for my access token, can I have the access token after users share?
This is my Code [UPDATED]:
<div id="fb-root"></div>
<script>
window.fbAsyncInit = function() {
FB.init({
appId : 'MYAPPID',
xfbml : true,
status : true,
cookie : true,
version : 'v2.3'
});
};
(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#xfbml=1&version=v2.3";
fjs.parentNode.insertBefore(js, fjs);
}(document, 'script', 'facebook-jssdk'));
</script>
<script>
function shareonfacebook(){
FB.ui(
{
method: 'feed',
name: 'Example',
link: 'https://www.example.com',
picture: 'Example.jpg',
caption: 'Example',
description: 'Example',
},
function (response) {
if (response && response.post_id) {
alert('Thanks!');
console.log( response );
} else {
alert('Oops!');
}
}
);
};
</script>

Answer 1

The post ID will only be there if you authorize a user with the publish_actions permission:
Only available if the user is logged into your app using Facebook and
has granted publish_actions. If present, this is the ID of the
published Open Graph story.
Side Note: If you need help with the Login part, here's an article about that: http://www.devils-heaven.com/facebook-javascript-sdk-login/