function OpenComments (c) {
    window.open(c,
                    'comments',
                    'width=480,height=480,scrollbars=yes,status=yes');
}

function OpenTrackback (c) {
    window.open(c,
                    'trackback',
                    'width=480,height=480,scrollbars=yes,status=yes');
}

function rnd_image(){
   var now = new Date();
   var sec_divide = now.getSeconds();
   rnd_number = Math.floor(sec_divide/5); // /20=0, 1, 2  /10=0, 1, 2, 3, 4, 5  etc...
   document.write('<img src="http://www.comerentenerife.com/imagenes/utensilio' + rnd_number +'.gif">');
}