Loading new content on the page via a link without changing the URL
<p>I am working on a social network website similar to facebook. But, I am facing a rather confusing stage in the programming.</p>

<p>I am done with the register/login/logout pages/scripts, and you can view profiles with the www.mywebsite.com/profile.php.</p>

<p>Now, I want to do what facebook does and allow users to click links while on their profile page (info, notes, photos) but never actually leave www.mywebsite.com/profile.php — just the appropriate content is printed to the screen.</p>

<p>How is this done? I am not asking anyone to code this for me, just point me in the right direction!</p>
