如何从php图库中生成xml

I am sort of new to php and totally new to ajax, so im still learning. The function below is what I currently have, it queries the database and outputs the images for my website. This works fine.

I am now trying to generate xml from the results to feed into javascript so that if the user wants to have a different view of the gallery - (2 rows instead of 4 for example), the page just updates without refreshing. Would I have to assign all the results to an array and then extract it with javascript ? Not sure where to even start. Please point me in a direction, many thanks !

<?php include 'library/connect.php';
$result = mysql_query("SELECT * FROM fproduct WHERE fproduct.category='Shirts'");
$cols=3;
echo "<table>";
do{
   echo "<tr>"; // adds a new row after the for loop has been executed for 4 times (4 columns)
    for($i=1;$i<=$cols;$i++){
        $row=mysql_fetch_array($result); 
        if ($row) {?>               
            <td> <a href = "Shirtbuy.php?id=<? echo $row['product_id'] ?>" ><img border="0" alt="pic" src="images/products/shirts/largethumbs/<? echo $row['pic']?>" /></a>     
            <br/>
            <b><?= $row['prod_name']?> </b><br/>    
            <b><?= $row['price']?>   </b><br/> 
            </td>
            <td width="100">&nbsp;</td> <?  
            }
        else{
            echo "<td>&nbsp;</td>"; //If there are no more records at the end, add a blank column
            }
    } 
} while($row);
    echo "</table>";
include 'library/close.php';

instead of XML use json

you can use php function json_enode to convert a php array to json format string.

$json_data = json_encode($result_array);

then pass it to your javascript & parse it

Json Encode

In javascript side. use jquery and parse json function

var obj = $.parseJSON(json_data);

Parse Json

Jquery Ajax sample request

  function send_data() {
    $.ajax({
      url   : "my_php_code.php", 
      type  : "POST",
      cache : false,
      data  : {
        the_key : the_value
      }
    });
  }