function despliega(opc,nfeed,trimfeed)
{
    if (document.getElementById(trimfeed+"_"+opc).className==''){
        document.getElementById(trimfeed+"_"+opc).className='oculto';
        document.getElementById(trimfeed+"_mas_rss_"+nfeed).className='';
        document.getElementById(trimfeed+"_menos_rss_"+nfeed).className='oculto';
    }else{
        document.getElementById(trimfeed+"_"+opc).className='';
        document.getElementById(trimfeed+"_mas_rss_"+nfeed).className='oculto';
        document.getElementById(trimfeed+"_menos_rss_"+nfeed).className='';
    }      
}