function topsyUrlinfoCallback(json) {
				var target_element = document.getElementById('topsy_tweets_counter');
				if ( !target_element ) {
								return false;
				}
				
				if ( json.response.trackback_total ) {
								target_element.innerHTML = '<span>'+json.response.trackback_total+'</span>';
				} else {
								target_element.innerHTML = '';
				}
}
script = document.createElement('script');
script.type = 'text/javascript';
script.src  = 'http://otter.topsy.com/urlinfo.js?callback=topsyUrlinfoCallback&url='+encodeURIComponent(url);
document.getElementsByTagName('head')[0].appendChild(script);