Si, a dire il vero c'ero arrivato subito dopo...

ho fatto così:

Codice PHP:
<script>
        
mrg=0;
        function 
righrarrow () {
            if(
mrg>-900){
                
mrg=mrg-180;
                
//$("#secondB").css("margin-left",mrg);
                //$("#secondB").animate({"margin-left":mrg},'slow');
                
$("#secondB").animate({"margin-left"mrg}, 100'easing');
            }
        }
        function 
leftrarrow () {
            if(
mrg!=0){
                
mrg=mrg+180;
                
//$("#secondB").css("margin-left",mrg);
                //$("#secondB").animate({"margin-left":mrg},'slow');
                
$("#secondB").animate({"margin-left"mrg}, 100'easing');
            }
        }
    
</script> 
..ma continua a non funziare...