PHP Post no refresh comment resolution

PHP Posts No Refresh comments
Little brother has a slight understanding of Ajax.
Want to implement a post without refreshing comments
Here is my Post's smarty template, peripherals a form, submitted to the background

HTML Code

  
   <{section name=num loop= $rss}>                           
  
           "height=" width=        
        <{$rss [num].username}>                        
  
   
   
            
   
    
    
 
     
 
      
Posted in <{$rss [num].msg_date}>
 
     
 
     
 
      
<{$rss [num].msg_text}>
 
     
 
     
 
      
Number of replies: <{$rss [num].msg_reply_count}>
 
     
 
    
  
   
   
            <{/section}>

What I want to ask is, is the backend using "echo" to output SQL results?
And what about the Ajax.post callback function of jquery? Paste the jquery code to me.

------Solution--------------------
Smarty can be combined seamlessly with xajax, why use jquery?

