var url = '';
var txt = '';

url='http://counter.laweb.es/plug_counter.php?id=' + idRabbit;
txt='<style>.boxcounter { display: block; border: 0px; width:140px; height: 70px;} </style>';
txt+='<iframe class="boxcounter" src="'+url+'" marginwidth="0"';
txt+=' marginheight="0" hspace="0" vspace="0" frameborder="0" scrolling="no"></iframe>';

document.write(txt);