<?php 
//include the information needed for the connection to MySQL data base server. 
// we store here username, database and password 
include("dbconfig.php");

// to the url parameter are added 4 parameters as described in colModel
// we should get these parameters to construct the needed query
// Since we specify in the options of the grid that we will use a GET method 
// we should use the appropriate command to obtain the parameters. 
// In our case this is $_GET. If we specify that we want to use post 
// we should use $_POST. Maybe the better way is to use $_REQUEST, which
// contain both the GET and POST variables. For more information refer to php documentation.
// Get the requested page. By default grid sets this to 1. 
$page = $_GET['page']; 

// get how many rows we want to have into the grid - rowNum parameter in the grid 
$limit = $_GET['rows']; 

// get index row - i.e. user click to sort. At first time sortname parameter -
// after that the index from colModel 
$sidx = $_GET['sidx']; 

// sorting order - at first time sortorder 
$sord = $_GET['sord']; 

// if we not pass at first time index use the first column for the index or what you want
if(!$sidx) $sidx =1; 

// connect to the MySQL database server 
$db = mysql_connect($dbhost, $dbuser, $dbpassword) or die("Connection Error: " . mysql_error()); 

// select the database 
mysql_select_db($database) or die("Error connecting to db."); 

// calculate the number of rows for the query. We need this for paging the result 
$result = mysql_query("SELECT COUNT(*) AS count FROM invheader"); 
$row = mysql_fetch_array($result,MYSQL_ASSOC); 
$count = $row['count']; 

// calculate the total pages for the query 
if( $count > 0 ) { 
              $total_pages = ceil($count/$limit); 
} else { 
              $total_pages = 0; 
} 

// if for some reasons the requested page is greater than the total 
// set the requested page to total page 
if ($page > $total_pages) $page=$total_pages;

// calculate the starting position of the rows 
$start = $limit*$page - $limit;

// if for some reasons start position is negative set it to 0 
// typical case is that the user type 0 for the requested page 
if($start <0) $start = 0; 

// the actual query for the grid data 
$SQL = "SELECT invid, invdate, amount, tax,total, note FROM invheader ORDER BY $sidx $sord LIMIT $start , $limit"; 
$result = mysql_query( $SQL ) or die("Couldn't execute query.".mysql_error()); 

// we should set the appropriate header information
if ( stristr($_SERVER["HTTP_ACCEPT"],"application/xhtml+xml") ) {
              header("Content-type: application/xhtml+xml;charset=utf-8"); 
} else {
          header("Content-type: text/xml;charset=utf-8");
}
echo "<?xml version='1.0' encoding='utf-8'?>";
echo "<rows>";
echo "<page>".$page."</page>";
echo "<total>".$total_pages."</total>";
echo "<records>".$count."</records>";

// be sure to put text data in CDATA
while($row = mysql_fetch_array($result,MYSQL_ASSOC)) {
echo "<row id='". $row[invid]."'>";            
            echo "<cell>". $row[invid]."</cell>";
            echo "<cell>". $row[invdate]."</cell>";
            echo "<cell>". $row[amount]."</cell>";
            echo "<cell>". $row[tax]."</cell>";
            echo "<cell>". $row[total]."</cell>";
            echo "<cell><![CDATA[". $row[note]."]]></cell>";
echo "</row>";
}
echo "</rows>"; 
?>

That is all. Save the file with name example.php and your first grid is done.