javascript - alert() box is coming up multiple times in jquery -

i clicking on simple add cart button add item cart , if item present gives error item already . goes , when click button second time , have close alert box twice , 3rd time click , have close alert box thrice , on ... goes on until refresh page , , same thing starts scratch

jquery code :

 function add()        {         $(document).ready(function()          {         $('#addtocart').submit(function() {            //$('#add-button').prop('disabled',true);     var user = $('#user').val();            var pid = $('#pid').val();         $.ajax({         type:       "post",         url:        "/devilmaycry/register?action=addtocart",         data:       {pid:pid ,user:user},         success:                        function()                      {                           alert("item has been added cart");                 },                   error:                      function(xhr)                      {                          if (xhr.responsetext=="already present")                             alert("item present in cart");                            else if(xhr.responsetext=="error")                              alert("item cannot added , server error");                 }                });               return false;      //e.preventdefault();     });          });        } 

servlet code :

if(n.equals("addtocart"))   {       string user = req.getparameter("user");       int pid = integer.parseint(req.getparameter("pid"));        k=o.addintocart(user,pid);       if(k==2)       {         res.setstatus(httpservletresponse.sc_internal_server_error);         pw.write("already present");       }       else if(k==0)       {         res.setstatus(httpservletresponse.sc_internal_server_error);         pw.write("error");       }   }  

error or success behavior same both

you need this

$(document).ready(function() { $('#addtocart').submit(function() {     //$('#add-button').prop('disabled',true);     var user = $('#user').val();     var pid = $('#pid').val();     $.ajax({         type: "post",         url: "/devilmaycry/register?action=addtocart",         data: {             pid: pid,             user: user         },         success: function() {             alert("item has been added cart");         },         error: function(xhr) {             if (xhr.responsetext == "already present")                 alert("item present in cart");              else if (xhr.responsetext == "error")                 alert("item cannot added , server error");         }     });     return false;     //e.preventdefault();  });}); 

no other event handlers required.