function MostViewed(opt){
    var divid='most-viewed';
    var HTMLold=document.getElementById(divid).innerHTML;
    var altura=document.getElementById(divid).offsetHeight;
    var anchura=document.getElementById(divid).offsetWidth;
    var transparencia='<div style="width:'+anchura+'px; height:'+altura+'px;" class="most_viewed" align="center"><img src="/loading.gif" style="margin-top:100px" /><\/div>';
    
    document.getElementById(divid).innerHTML=transparencia+HTMLold;
    
    var callback = {
        success: function(o) {
            document.getElementById(divid).innerHTML=o.responseText;
        },
        failure: function(o) {
           document.getElementById(divid).innerHTML=HTMLold;
        }
    }
    var transaction = YAHOO.util.Connect.asyncRequest('GET', "/mostviewed.php?option="+opt, callback, null);
    return false;
}