var xmlhttp;
    var roll;
    var category;
    var timer;
        
    category = 0;
    roll = 0;
    
    function beginRoll(){
        
        timer = setInterval( 'rollCategoryList()', 5000);         
        
    }
    
    function stopRoll(){
        
        clearInterval( timer);
        
    }
    
    function rollCategoryList(){
        
        roll ++;
        
        if( roll == 1) category = roll;
        
        else category = roll + 1;

        getCategoryList( category);
        
        if( roll == 4) roll = 0;
        
    }
    
    function getCategoryList( si){

        var url;
        
        category = si;

        if( category > 1){
        
            roll = category - 1; 
    
            if( roll == 4) roll = 0;
    
        }
    
        url = './xml/xml_article_main_list.xml';

        if( window.XMLHttpRequest) xmlhttp = new XMLHttpRequest();
        else if( window.ActiveXObject) xmlhttp = new ActiveXObject('Microsoft.XMLHTTP');
        
        xmlhttp.open( 'GET', url, false);
              
        if( navigator.appName == 'Netscape'){

            xmlhttp.send( null);
            setCategoryList();
        
        }
        
        else{

            xmlhttp.onreadystatechange = setCategoryList;
            xmlhttp.send( null);
            
        }        
        
    }

    function setCategoryList(){
        
        var i;
        var xmlroot, xmlsingle;
        var serialno, subject, brief, thumb, publish, url;
        var content;

        if( xmlhttp.readyState == 4 && xmlhttp.status == 200){ 

            xmlroot = xmlhttp.responseXML;

            xmlsingle = xmlroot.selectSingleNode('./root/result/item[@category=\'' + category + '\']');

            if( xmlsingle){
                
                serialno = xmlsingle.selectSingleNode('./serialno').firstChild.nodeValue;
                subject = xmlsingle.selectSingleNode('./subject').firstChild.nodeValue;
                brief = xmlsingle.selectSingleNode('./brief').firstChild.nodeValue;
                thumb = xmlsingle.selectSingleNode('./thumb').firstChild.nodeValue;
                            
                publish = '';
                                
                if( category == 1) publish = xmlsingle.selectSingleNode('./publish').firstChild.nodeValue;
                
                url = 'article_view.asp?sn=' + serialno;
                
                content = '     <table width="528" cellpadding="0" cellspacing="0">';
                content += '      <tr>';
                
                if( category == 1) content += '       <td width="132" height="24" align="center" class="white_12x_b" background="./images/tab_1.png"><div style="padding-top: 5px;" onmouseout="javascript: beginRoll();">熱門新聞</div></td>';
                
                else content += '       <td width="132" height="24" align="center" class="black_12x_b" background="./images/tab_2.png"><div style="padding-top: 5px;" onmouseover="javascript: getCategoryList(1); stopRoll();"><a href="javascript:;" class="black_lnk">熱門新聞</a></div></td>';
                   
                if( category == 3) content += '       <td width="132" height="24" align="center" class="white_12x_b" background="./images/tab_1.png"><div style="padding-top: 5px;" onmouseout="javascript: beginRoll();">市場話題</div></td>';
                
                else content += '       <td width="132" height="24" align="center" class="black_12x_b" background="./images/tab_2.png"><div style="padding-top: 5px;" onmouseover="javascript: getCategoryList(3); stopRoll();"><a href="javascript:;" class="black_lnk">市場話題</a></div></td>';
                    
                if( category == 4) content += '       <td width="132" height="24" align="center" class="white_12x_b" background="./images/tab_1.png"><div style="padding-top: 5px;" onmouseout="javascript: beginRoll();">技術頻道</div></td>';
                
                else content += '       <td width="132" height="24" align="center" class="black_12x_b" background="./images/tab_2.png"><div style="padding-top: 5px;" onmouseover="javascript: getCategoryList(4); stopRoll();"><a href="javascript:;" class="black_lnk">技術頻道</a></div></td>';                                        

                if( category == 5) content += '       <td width="132" height="24" align="center" class="white_12x_b" background="./images/tab_1.png"><div style="padding-top: 5px;" onmouseout="javascript: beginRoll();">關鍵圖表</div></td>';
                
                else content += '       <td width="132" height="24" align="center" class="black_12x_b" background="./images/tab_2.png"><div style="padding-top: 5px;" onmouseover="javascript: getCategoryList(5); stopRoll();"><a href="javascript:;" class="black_lnk">關鍵圖表</a></div></td>';

                content += '      </tr>';
                content += '      <tr><td width="528" height="2" colspan="4" bgcolor="#909090"></td></tr>';
                content += '      <tr>';
                content += '       <td width="528" align="center" colspan="4" bgcolor="#EFEFEF">';
                content += '        <div onmouseover="javascript: stopRoll();" onmouseout="javascript: beginRoll();">';
                content += '         <table width="500" border="0" cellpadding="0" cellspacing="0">';
                content += '          <tr><td height="3" colspan="2"></td></tr>';
                content += '          <tr><td height="20" colspan="2" class="black_11x">' + publish + '</td></tr>';
                content += '          <tr><td height="22" colspan="2" class="black_15x_b"><a href="' + url + '" class="blue_lnk">' + subject + '</a></td></tr>';
                content += '          <tr><td height="3" colspan="2"></td></tr>';
                content += '          <tr>';
                content += '           <td width="160" align="left" valign="top" rowspan="2"><a href="' + url + '"><img src="' + thumb + '" width="150" height="150" class="pt"></a></td>';
                content += '           <td width="340" class="black_13x" valign="top"><div style="width:340px;height:130px;overflow:hidden">' + brief + '</div></td>';
                content += '          </tr>';
                content += '          <tr><td height="22" align="right" valign="bottom" class="black_12x"><a href="' + url + '" class="black_lnk">詳全文</a> <img src="./images/arrow_blue.gif" width="11" height="11"></td></tr>';
                content += '          <tr><td height="13" colspan="2"></td></tr>';  
                content += '         </table>';
                content += '        </div>';
                content += '       </td>';
                content += '      </tr>';  
                content += '     </table>';
                
                document.getElementById('ArticleMain').innerHTML = content;
                
            }

        }    
        
    }