how to use ajax to reload partial page content without external file?

[zoldos]

I run a social networking site and it has an advanced newsfeed feature. I want to use ajax and a clickable link to refresh just the newsfeed and not the entire page. The code is held in a javascript tab as seen below and I've already added a basic link to refresh the entire page. The specific code that produces the newsfeed is here:

{he_wall_display object='userhome' object_id=$user->user_info.user_id}

and cannot be held in an external file.

Here is the code with the tab:

<div id='profile_activity'{if $v != 'activity'} style='display: none;'{/if}><br>
-=<a href="javascript:location.reload(true);" target="_self">Click here</a> and then click the activity tab again to refresh site updates=-<br>
{he_wall_display object='userhome' object_id=$user->user_info.user_id} 
</div>

Any suggestions would be greatly appreciated! Thanks!