function SetPageNumber(NewPage)
{
    var loc=location.href;
    var Qstring=loc.split('?');
    if(Qstring.length==1)
    {
        //alert('if');
        loc += '?pn=' + NewPage;
    }
    else
    {
        //alert('else');
        var found=false;
        var QParams=Qstring[1].split('&');
        for(i=0;i<QParams.length;i++)
        {
            if(QParams[i].substring(0,3)=='pn=')
            {
                loc=loc.replace(QParams[i],'pn=' + NewPage);
                found=true;
            }
        }
        if(!found)
            loc += '&pn=' + NewPage;
    }
    document.location=loc;
}