Newsletter with refresh ajax

Question

I’m trying to send this form through ajax and I’m not getting, is there something wrong? I’m beating my head against this for four hours without success.

Note: I am developing via wordpress and I am using a plugin called Newsletter to store the emails captained by the form. I already managed to make it work once, but in another office and on another site, but I ended up losing the code that works and I’m trying again to make it work.

        var fmr = $('#formsnewslatetr');
        var dados = $('#formsnewslatetr').serialize();
        fmr.submit(function (e){
             e.preventDefault();

             $.ajax(
           {
               type: fmr.attr('method'),
               url: fmr.attr('action'),
               data: dados,
               success: function ( response )
               {
                   $('.success-box').fadeIn();
                   var retorno = 'true';
                   fmr.fadeOut();

                },
               error: function ( txt )
               {
                   alert( "ERRO" );
               }
           }
       );
}); 

<form id="formsnewslatetr" method="post" action="/?na=s" onsubmit="return newsletter_check(this)" class="form-inline w-100">
    <div class="form-group w-100">
          <input class="i-email" type="email" name="ne" id="email" placeholder="Email" required="">
          <input class="b-email" type="submit" value="Assinar">
    </div>
</form>

Answer 1

The form is being submitted via button submit passing through function newsletter_check(this) waiting for a return. In this case, the fmr.submit (because if it was in memory -- it is not in memory because it seems to be inside a function that has not yet been executed --, the form would be sent 2x: one by the button submit and another by frm.submit).

In this case it is still necessary to put a return false; at the end of the function to prevent the page from being redirected.

In view of this, your code should have this structure:

function newsletter_check(formulario){ // o parâmetro "formulário" apenas como exemplo
   var fmr = $('#formsnewslatetr');
   var dados = $('#formsnewslatetr').serialize();
   $.ajax({
      type: fmr.attr('method'),
      url: fmr.attr('action'),
      data: dados,
      success: function(response){
         $('.success-box').fadeIn();
         var retorno = 'true';
         fmr.fadeOut();
      },
      error: function(txt){
         alert( "ERRO" );
      }
   });
   return false;
}

If you want to do some kind of e-mail validation, just put this validation at the beginning of the function and if it is not validated, add return false; to prevent the function from entering Ajax.