your code should be something like this
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js">
js code
<script type="text/javascript">
jQuery(document).ready(function(){
jQuery("#contain").load("http://examplepage.com/forum/showthread.php?tid=NN #pid_NN");
});
</script>