how to get form id from ajax and set it in click function in symfony2

how to get form id from ajax and set it in click function in symfony2

i want to store id in global variable and then store this id for form edit
here is my xml request:
if($request->isXmlHttpRequest()) {
$response = new Response();
$output = array('success' => true, 'title' => $entity->gettitle(),
'id' => $entity->getId(), 'notes' => $entity->getnotes(),
'accountid' => $entity->getaccountid(), 'clientid' =>
$entity->getClientID(), 'status' => $entity->getstatus(),
'totalamount' => $entity->getTotalAmount(), 'paidamount' =>
$entity->getPaidAmount(), 'balanceamount' =>
$entity->getBalanceAmount(), 'createdby' =>
$entity->getcreatedby(), 'updatedby' => $entity->getupdatedby(),
'createddatetime' => $entity->getcreateddatetime(),
'updateddatetime' => $entity->getupdateddatetime());
$response->headers->set('Content-Type', 'application/json');
$response->setContent(json_encode($output));
return $response;
}
and here is my ajax code:
$("form").submit(function(e) {
e.preventDefault();
var url = $(this).attr('action');
var data = $(this).serialize();
$.ajax({
type: "POST",
url: url,
data: data,
}).done(function( result ) {
invoiceid=result.id;
if(result.success) {
$('#result').css({'color':'black','background-color':'#8F8','display':'Block','width':'200px'});
$('#result').html('Invoices Record Inserted');
setTimeout(function(){
$('#result').hide();
},3000);
}
});
this.reset();
});
$("#edit").click(function(){
window.location.href= "{{ path('invoices_edit', {'id': invoiceid }) }}";
});
when i alert invoiceid then it show value of result.id but invoiceid not
pass to click function,how i do this?