Page Submission Refresh related issues

Page Submission Refresh Issue
Made a simple page: The above row of query criteria, click on the query, the lower half of the results of the query display;

Now the problem is, click on the query, how to make the upper part of the non-refresh, is the previous input query information is not cleared, please let us know.
------to solve the idea----------------------
Typical AJAX applications
------to solve the idea----------------------
Ajax can do it.
To write you a simple example:
Client.html

  
 
 
  
  



    Key
    
    

server.php

 
 $key = isset ($_post[' key ')? $_post[' key ']: ';
Header (' Content-type:application/json;charset=utf-8 ');
echo json_encode (' key ' and ' = ' key you entered is: '. $key));
?>

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