display block is not working on jQuery

Question

I got the following jQuery script:

    $.ajax({
        url: "_scripts/_php/_validacoes/cadastrarCelulaMembro.php",
        type: "POST",
        dataType: "json",
        data: {   
             idPastor : $("#idPastor").val(),
             idRede : $("#idRede").val(),
             idRegiao : $("#idRegiao").val(),
             idArea : $("#idArea").val(),
             idSetor : $("#idSetor").val(),
             idCelula : $("#idCelula").val(),
             idMembro : $("#idMembro").val()
        },
        beforeSend: function() {
            $("#buttonCadastrarCelulaMembro").attr('display','none');
            $("#imgCarregando").attr('display','block');
        },
        success: function (result) {
            $("#buttonCadastrarCelulaMembro").attr('display','block');
            $("#imgCarregando").attr('display','none');
            if (result[0] == "Erro")
                $(".resposta").html(result[1]);
            else
                $(".resposta").html(result[1]);
        }
    });
  }

The idea is to enter the $.ajax and before sending the form, give a display: none in the button and a display: block in a image of Loader

beforeSend: function() {
    $("#buttonCadastrarCelulaMembro").attr('display','none');
    $("#imgCarregando").attr('display','block');
},

And, after receiving the return of PHP, do the reverse process.

success: function (result) {
                $("#buttonCadastrarCelulaMembro").attr('display','block');
                $("#imgCarregando").attr('display','none');
...

But this is not happening.

Where am I going wrong?

This is the end of the form:

...

    <button id="buttonCadastrarCelulaMembro" class="button">Cadastrar Membro na Célula</button>
    <img id="imgCarregando" style="display: none" src="_imgs/carregando.gif" />
    <br />
<div class="resposta"></div>
</div> 
<div class="dadosMembro"></div>

Buuton class CSS

.button {
    width: 250px;
    height: 30px;
    margin: 3px;
}

Answer 1

Change attr for css. Thus remaining:

$("#buttonCadastrarCelulaMembro").css('display','none');
$("#imgCarregando").css('display','block');

Answer 2

I forgot that css is not attribute and yes style.

In case, it has to be

.css() 

and not

.actribute() 

or

.prop()