// JavaScript Document

function ajaxGetLevel(targetID, nid, level) {
	var http_request = false;
	var url = "./ajax_selcat.php";
	
	if (window.XMLHttpRequest) { // Mozilla, Safari,...
	  http_request = new XMLHttpRequest();
	} else if (window.ActiveXObject) { // IE
	  try {
		http_request = new ActiveXObject("Msxml2.XMLHTTP");
	  } catch (e) {
		try {
		  http_request = new ActiveXObject("Microsoft.XMLHTTP");
		} catch (e) {}
	  }
	}
	
	if (!http_request) {
	  alert('Giving up :( Cannot create an XMLHTTP instance');
	  return false;
	}
	// 定義事件處理函數為 alterContents()
	http_request.onreadystatechange = function() { getNode(targetID, level, http_request); };
	
	// show loading icon
	if (level == 1)
		document.getElementById("tr_category").style.display = "inline";
	else
		document.getElementById("tr_subCategory").style.display = "inline";
	var target = document.getElementById(targetID);
	target.innerHTML = "<img src=\"images/ajax_loading.gif\" alt=\"LOADING ...\" />";
	
	// IE 6.x 和 Firefox 1.5.x 皆要 encodeURI()
	
	url = url + "?nid=" + nid + "&amp;seed=" + Date();
	http_request.open('GET', url, true);
	http_request.send(null);
}
	
function getNode(targetID, level, http_request) {
	if (http_request.readyState == 4) {
      if (http_request.status == 200) {
        var xmldoc = http_request.responseXML;
        var nodes = xmldoc.getElementsByTagName("mydata");
        var target = document.getElementById(targetID);
		var outputContent = "";
		
		// clear target content
		target.innerHTML = "";		
		
		if (level == 1) {
			outputContent += "<select name=\"catId\" style=\"width:265px;\" class=\"box\" onChange=\"ajaxGetLevel('div_subCategory', this.value, '2')\">\n<option value=\"\">Please Select</option>\n";
			document.getElementById("div_subCategory").innerHTML = "<select name=\"subId\" style=\"width:265px;\" class=\"box\">\n<option value=\"\">Please Select</option>\n";
		} else {
			outputContent += "<select name=\"subId\" style=\"width:265px;\" class=\"box\">\n<option value=\"\">Please Select</option>\n";
		}
		// add news
		for(var i=0; i<nodes.length; i++) {
		  thisId = nodes[i].getAttribute("id");
		  thisValue = nodes[i].getAttribute("name");
		  //thisValue = nodes[i].firstChild.nodeValue;
		  
		  outputContent += "<option value=\""+thisId+"\">"+thisValue+"</option>\n";
		}
		outputContent += "</select>";
				
		// set target content
		target.innerHTML = outputContent;	
		
      } else {
        alert('There was a problem with the request.');
      }
    }
}