<?php
$type = $GET_["type"];
$node = array();
....
$result = mysql_query($query);
	//Обработка и вывод результатов SQL-запроса
	while ($row = mysql_fetch_array($result, MYSQL_ASSOC)){
//usleep(500000);
$id = $row["STR_ID"];
$title = $row["STR_DES_TEXT"];
$folder = $row["DESCENDANTS"];

	$node[] = "{ id: $id, type: $type, title: '$title', isFolder: $folder }";
}
echo '['.implode(',',$node).']';

function tree(id, url) {
	var element = document.getElementById(id)

	function hasClass(elem, className) {
		return new RegExp("(^|\\s)"+className+"(\\s|$)").test(elem.className)
	}

	function toggleNode(node) {
		var newClass = hasClass(node, 'ExpandOpen') ? 'ExpandClosed' : 'ExpandOpen'
		var re =  /(^|\s)(ExpandOpen|ExpandClosed)(\s|$)/
		node.className = node.className.replace(re, '$1'+newClass+'$3')
	}

	function load(node) {

		function showLoading(on) {
			var expand = node.getElementsByTagName('DIV')[0]
			expand.className = on ? 'ExpandLoading' : 'Expand'
		}


		function onSuccess(data) {
			if (!data.errcode) {
				onLoaded(data)
				showLoading(false)
			} else {
				showLoading(false)
				onLoadError(data)
			}
		}


		function onAjaxError(xhr, status){
			showLoading(false)
			var errinfo = { errcode: status }
			if (xhr.status != 200) {
				errinfo.message = xhr.statusText
			} else {
				errinfo.message = 'Error Data11'
			}
			onLoadError(errinfo)
		}


		function onLoaded(data) {
    for(var i=0; i<data.length; i++) {
    var child = data[i]
                
    var li = document.createElement('LI')
    li.className = "Node Expand" + (child.isFolder ? 'Closed' : 'Leaf')
    if (i == data.length-1) li.className += ' IsLast'

    li.id = child.id

    li.innerHTML = '<div class="Expand"></div><div class="Content">'+child.title+'</div>'
    if (child.isFolder) {
    li.innerHTML += '<ul class="Container"></ul>'
    }
 node.getElementsByTagName('UL')[0].appendChild(li)
                 
  }
 node.isLoaded = true
 toggleNode(node)
}

		function onLoadError(error) {
			var msg = "Error"+error.errcode
			if (error.message) msg = msg + ' :'+error.message
			alert(msg)
		}


		showLoading(true)

		$.ajax({

            url: url + '?id=' + node.id + '&type=' + node.type,// вот в этом месте id передаётся в data.php. Должно бы, точнее.			
			data: node.id,
			dataType: "json",
			success: onSuccess,
			error: onAjaxError,
			cache: false
		})
	}

	element.onclick = function(event) {
		event = event || window.event
		var clickedElem = event.target || event.srcElement

		if (!hasClass(clickedElem, 'Expand')) {
			return 
		}

		
		var node = clickedElem.parentNode
		if (hasClass(node, 'ExpandLeaf')) {
			return 
		}

		if (node.isLoaded || node.getElementsByTagName('LI').length) {
			toggleNode(node)
			return
		}

		if (node.getElementsByTagName('LI').length) {
			toggleNode(node)
			return
		}

		load(node)

	}

}

$.ajax({

            url: url,			
			data: "id=" + node.STR_ID + "type=" + node.type,
			dataType: "json",
			success: onSuccess,
			error: onAjaxError,
			cache: false
		})

		$.ajax({

            url: url,			
			data: "id=10110&type=21886",
			dataType: "json",
			success: onSuccess,
			error: onAjaxError,
			cache: false
		})