How to post HTML content in facebook wall using facebook api in php

Question

How to post HTML content in facebook wall using facebook api in php

I have used below codes but not working

$result = $facebook->api('/me/feed/','post',array( 'message' => '<h1>This is my demo Face book application!</h1>'));

And I used as below code using php concatenate the HTML string

 $result = $facebook->api('/me/feed/','post',array( 'message' => 'This is my demo Facebook application!' . $htmlStr));

but not working and getting below error

OAuthException: (#1) An unknown error occurred

Any please help me.