var pass = 168;
var content = 'new!';
var currentDate = new Date();
var spans = document.getElementsByTagName('span');
for (i = 0; i < spans.length; i++) {
    if(spans[i].getAttribute('class') == 'new' ||
     spans[i].getAttribute('className') == 'new') {
        time = spans[i].childNodes[0].nodeValue.split(":");
        var entryDate = new Date(time[0], time[1]-1, time[2], time[3], time[4], time[5]);
        var now = (entryDate.getTime() - currentDate.getTime())/(60*60*1000);
        now = Math.ceil(now);
        if(-now <= pass){
            spans[i].innerHTML = content;
        }
    }
}


// access
document.write("<img src='http://www.naigai-group.co.jp/cgi-bin/acc/acclog.cgi?");
document.write("referrer="+document.referrer+"'>");