// JavaScript Document
function caller(action,args,container,metod) {
$.ajax({
type : metod,
url : action,
cache: false,
data: action+args,
dataType: 'html',
success: function(data) {
$(container).html(data).fadeIn(300);
},
error: function(XMLHttpRequest, textStatus, errorThrown) {
$(container).html('There was an error.').fadeIn(300);
}
});
}

var auto_refresh = setInterval(  
function(){  
caller('bacheca.php','','#content','GET'); 
$("#content").fadeIn("slow");
$("#content").fadeOut("slow");
}, 500000);