var xmldom;
    var currentItem;
    var iCount;
    
    iCount = 0;
    
    function loadGalleryData(){
        
        var element;
        
        element = document.getElementById('gallery-data');
        
        if( window.ActiveXObject){ 
        
            xmldom = new ActiveXObject("Microsoft.XMLDOM"); 
            xmldom.async = false; 
            xmldom.loadXML( element.value); 

        } 

        else{ 
            
            var parser;
            
            parser = new DOMParser();   
        
            xmldom = parser.parseFromString( element.value, 'text/xml');   

        } 

        currentItem = 1;

    }
    
    function viewItem( item){

        var xmlroot;
        var xmlnodes;
        var sum;
        var i;
        var name, notes;

        iCount ++;

        if( iCount == 15){

            refreshAdvLink();

            iCount = 0;
        
        }
        
        sendPageView();
        
        xmlroot = xmldom.documentElement;
        
        xmlnodes = xmlroot.selectNodes('./single');
        
        sum = xmlnodes.length;

        if( item > sum) i = 0;
        
        else if( item < 1) i = sum - 1;
        
        else i = item - 1;

        name = xmlnodes[i].attributes.getNamedItem('name').value; 
        notes = xmlnodes[i].attributes.getNamedItem('notes').value; 

        currentItem = i + 1;

        if( notes.length == 0) notes = document.getElementById('subject').value;

        document.getElementById('current-name').src = name;
        document.getElementById('current-item').innerHTML = currentItem;
        document.getElementById('current-notes').innerHTML = notes;
        
    }

    function nextItem(){
             
        var i;
        
        i = currentItem + 1;
        
        viewItem(i);
        
    }
    
    function prevItem(){

        var i;
        
        i = currentItem - 1;
        
        viewItem(i);
        
    }

    function jumpPage( page){
        
        var pagesize;
        var totalpages, currentpage;
        var n, m;
        var xmlroot;
        var content;
        var name;

        content = '';

        xmlroot = xmldom.documentElement;
        
        xmlnodes = xmlroot.selectNodes('./single');
        
        sum = xmlnodes.length;

        pagesize = 10;
        totalpages = 1;
        currentpage = page;

        totalpages = parseInt( sum / pagesize);
     
        if( sum % pagesize != 0) totalpages ++;

        if( currentpage > totalpages) currentpage = 1;
        if( currentpage < 1) currentpage = totalpages;

        content += '<a href="javascript: jumpPage(' + ( currentpage - 1 ) + ');" class="thumbs-prev">上一頁</a>';
        content += '<a href="javascript: jumpPage(' + ( currentpage + 1 ) + ');" class="thumbs-next">下一頁</a>';

        content += '<ul class="thumb-pic">';
        
        if( sum > 0){

            n = ( currentpage - 1) * pagesize;
            
            m = currentpage * pagesize;

            if( m > sum) m = sum;
        
            for( i = n; i < m; i ++){

                name = xmlnodes[i].attributes.getNamedItem('name').value.replace( 'GI', 'GT');

                if( currentItem == ( i + 1)) content += '<li><a href="javascript: viewItem(' + ( i + 1 ) + ');"><span></span><img src="' + name + '" /></a></li>';

                else content += '<li><a href="javascript: viewItem(' + ( i + 1 ) + ');"><span></span><img src="' + name + '" /></a></li>';
                
            }
            
        }
        
        content += '</ul>';
        
        document.getElementById('item-list').innerHTML = content;
        
    }