var gkIndex = -1;
var gkArr = new Array();
var gkTime = null;
var gkLastId = null;
var gkPlayDuration = 10000;

function play()
{
    next();
    gkTime = window.setInterval("next();", gkPlayDuration);
   
    $('btplay').style.display='none';
    $('btstop').style.display='block';
}

function stop()
{
    window.clearInterval(gkTime);
    
    $('btstop').style.display='none';
    $('btplay').style.display='block';
}

function next()
{
    gkIndex++;
    
    if(gkIndex >= gkArr.length)
        gkIndex = 0;
        
    show();
}

function previous()
{
    gkIndex--;
    
    if(gkIndex < 0)
        gkIndex = 0;
        
     show();
}

function showById(leadId)
{
    stop();
    
    for(var i=0;i<gkArr.length;i++){
        if(gkArr[i] == leadId)
        {
            show(i);
            break;  
        }  
    }
}

function show(index)
{
    if(index != null)
        gkIndex = index;
        
    var leadid = gkArr[gkIndex];
   
     var leaddiv = $("previewdiv" + leadid);
     var lastdiv = $("previewdiv" + gkLastId);
     var lasttitle = $("title" + gkLastId);
    
     if(leaddiv == null)
        return;
        
     if(lastdiv != null)
        lastdiv.style.display = "none";
     
     if(lasttitle != null)
        lasttitle.className = "gk_news";
        
     leaddiv.style.display = 'block';
    
     var titlediv = $("title" + leadid);
     
     if(titlediv != null)
        titlediv.className = "gk_news_sel";
        
     gkLastId = leadid;
        
}