var inum = 0;
	var getData;
	var category;
	var numOfItems;
	var imgpath = "images/galleries/";

	function getXML(url)
	{
		var a = Math.random()*100;
		//alert(a)
		sendRequest(url, readXML, 'GET', a);
	}
	function readXML(req)
	{
		x = req.responseXML.getElementsByTagName('category');
		category = x[0].childNodes[0].nodeValue;
		
		getItems = req.responseXML.getElementsByTagName('item');
		numOfItems = getItems.length;
		
		showImg(inum);
	}

	
	function clearContents(){
		var childs = document.getElementById("photoarea").childNodes;
		var l = childs.length;
		//alert(l)
		for(var i =0; i < l ; i++)
		{
			document.getElementById("photoarea").removeChild(childs[0])
		}
	}
	
	function showImg(inum){
		
		
		/* ################################################################
		
			make format inside photo area
			
			    <img src="images/galleries/aboutus/photo_01_01.jpg" alt="" />
                <div class="cls pareamid">
                    <ul class="left">
                        <li class="prevoff">Previous</li>
                        <li class="nexton"><a href="#">Next</a></li>
                    </ul>
                    <ul class="right">
                    	<li>&nbsp;</li>
                        <li class="count">Image 1 of 3</li>
                    </ul>
                </div>
                <div class="description">
                	<p> </p>
                </div>
		
		################################################################ */
		
		
		clearContents(); //clear all contents in photoarea
		
		
		/* get Data from XML Object */
		
		var n;		
		
		n = getItems[inum].getElementsByTagName('title');
		var title = 'Photo';
		if(n[0].hasChildNodes()){
			var title = n[0].childNodes[0].nodeValue;
				title = title.replace(/&lt;/g , '<')
				title = title.replace(/&gt;/g , '>')
		}
		
		n = getItems[inum].getElementsByTagName('image');
		var imagename = n[0].childNodes[0].nodeValue;

		n = getItems[inum].getElementsByTagName('description');
		var description = n[0].childNodes[0].nodeValue;
			description = description.replace(/&lt;/g , '<')
			description = description.replace(/&gt;/g , '>')
		
		
		
		/* make html */
		
		var imgElem = document.createElement('img');
		imgElem.setAttribute('src', imgpath+category+imagename);
		imgElem.setAttribute('alt', title);
		
		
		
		var infoElem = document.createElement('div');
		infoElem.setAttribute('class', "cls pareamid");
		infoElem.setAttribute('className', "cls pareamid");

		var naviElem =  document.createElement('ul');
		naviElem.setAttribute('class', "left");
		naviElem.setAttribute('className', "left");

		var countElem =  document.createElement('ul');
		countElem.setAttribute('class', "right");
		countElem.setAttribute('className', "right");
		
		
		var countItem = '<li>&nbsp;</li><li class="count">图像 ' + (inum + 1) + ' 共 ' + numOfItems + '</li>';
		countElem.innerHTML = countItem;
		
		
		var prevElem = getPrev(inum);
		var nextElem = getNext(inum);	
		naviElem.innerHTML = prevElem + nextElem;
		
		infoElem.appendChild(naviElem);
		infoElem.appendChild(countElem);
		

		var descElem = document.createElement('div');
		descElem.setAttribute('class', "description");
		descElem.setAttribute('className', "description");
		
		var pElem = document.createElement('p');
		pElem.innerHTML = description;
		
		descElem.appendChild(pElem);


		document.getElementById("photoarea").appendChild(imgElem);
		document.getElementById("photoarea").appendChild(infoElem);
		document.getElementById("photoarea").appendChild(descElem);
	}
	
	
	
	function getPrev(inum)
	{
		var aElem = "";
		
		if(inum <= 0)
		{
			aElem = '<li class="prevoff">上一个图像</li>';
		}else{
			inum--;
			aElem = '<li class="prevon"><a href="#" onclick="showImg('+inum+')">上一个图像</a></li>';
		}
		
		return aElem;
	}
	
	
	function getNext(inum)
	{
		
		var imax = numOfItems - 1;

		var aElem ="";
		
		if(inum==imax)
		{
			aElem = '<li class="nextoff">下一个图像</li>';
		}else{

			inum++;
			aElem = '<li class="nexton"><a href="#" onClick="showImg('+inum+')">下一个图像</a></li>';
		}
		
		return aElem;
	}
	
	function changeValues(v){
		document.getElementById("target").childNodes[0].src=v
	}