HTML - Change\Update page contents without refreshing\reloading the page

You've got the right idea, so here's how to go ahead: the onclick handlers run on the client side, in the browser, so you cannot call a PHP function directly. Instead, you need to add a JavaScript function that (as you mentioned) uses AJAX to call a PHP script and retrieve the data. Using jQuery, you can do something like this:

<script type="text/javascript">function recp(id) {  $('#myStyle').load('data.php?id=' + id);}</script><a href="#" onClick="recp('1')" > One   </a><a href="#" onClick="recp('2')" > Two   </a><a href="#" onClick="recp('3')" > Three </a><div id='myStyle'></div>

Then you put your PHP code into a separate file: (I've called it data.php in the above example)

<?php  require ('myConnect.php');       $id = $_GET['id'];  $results = mysql_query("SELECT para FROM content WHERE  para_ID='$id'");     if( mysql_num_rows($results) > 0 )  {   $row = mysql_fetch_array( $results );   echo $row['para'];  }?>

jQuery will do the job. You can use either jQuery.ajax function, which is general one for performing ajax calls, or its wrappers: jQuery.get, jQuery.post for getting/posting data.Its very easy to use, for example, check out this tutorial, which shows how to use jQuery with PHP.