function showMoreClusters()
{    
    var elms = document.getElementById('hiddencluster');    
    
    while(elms)
    {   
        elms.id = 'showncluster';
        elms.style.display='block';
        elms = document.getElementById('hiddencluster');        
    }
    
    var hide_elm = document.getElementById('moreclusters');
    var show_elm = document.getElementById('fewerclusters');
    
    hide_elm.style.display='none';
    show_elm.style.display='block';
}

function showFewerClusters()
{
    var elms = document.getElementById('showncluster');    
    
    while(elms)
    {   
        elms.id = 'hiddencluster';
        elms.style.display='none';
        elms = document.getElementById('showncluster');        
    }
    
    var show_elm = document.getElementById('moreclusters');
    var hide_elm = document.getElementById('fewerclusters');
    
    hide_elm.style.display='none';
    show_elm.style.display='block';
}