$(document).ready(function(){
            
            $("#re_captcha").click(function(){
                    $("#captcha").attr("src","");
                    $("#captcha").attr("src","imageverify.php?unique="+unique());
                });
            
            function unique(){
               var d, s = "";
               var c = "!";
               d = new Date();
               s += d.getHours() + c;
               s += d.getMinutes() + c;
               s += d.getSeconds() + c;
               s += d.getMilliseconds();
               return(s);
            }
     });