<div id="gridbox" width="500px" height="250px" style="background-color:white;overflow:hidden"></div>
<script>
 
        mygrid = new dhtmlXGridObject('gridbox');
        ...
        mygrid.kidsXmlFile="pro_treeGrid_dynamic.php";
        mygrid.loadXML("treeGrid_dynamic.php");
        
    ==================  pro_treeGrid_dynamic.php ========================
    <?php
    //the php file must be recognized as XML document so necessary header sent
    header("Content-type:text/xml");
    //default xml file header (UTF-8 is a common value, but in some cases another encoding must be used)
    print('<?xml version="1.0" encoding="UTF-8"?>');
 
    //the script receive a parent item id from GET scope as my_script.php?id=PARENT_ID
    //if parent id not sent - top level in related sample - then  set it equal to 0
    if (!isset($_GET['id']))  $_GET['id']=0;
    //write top tag of xml document, the parent attribute contain id of parent row
    print ("<rows parent='".$_GET['id']."'>");
 
    //in real code here you must take records from DB
    //in sample we simple create a 20 dummy records
    for($i = 0;$i<20;$i++){
        //row tag contain a id and xmlkids attributes
        //if xmlkids attribute exists and is not empty - the row will be drawn as expandable
        //in our sample each 4th row will be expandable
        print "<row id='a_{$_GET['id']}_{$i}' xmlkids='".(($i%4==0)?1:"")."'>";
        //value of row
        print ("<cell image='folder.gif'>Item {$_GET['id']}:{$i}</cell>");
        //close row tag
        print ("</row>");
    }
    //after drawing all childs of current row, the main tag must be closed
    print("</rows>");</script>