$(function(){
   // Share facebook
   $('.share_facebook').click(function(e) {
       url = this.href;
       title = $(this).attr('title');

       share_facebook(url, title);

       return false;
   });

});

function share_facebook(url, title) {
    //url = url.replace(/_/, "-");
    window.open('http://www.facebook.com/sharer.php?u='+encodeURIComponent(url)+'&t='+encodeURIComponent(title),'sharer','toolbar=0,status=0,width=626,height=436');

    pageTracker._trackEvent('facebook', 'share_site');
}