Download with Post metod

[Elias]

I'm totally lost here, need help

How to Download a File with Post metod

The page I'm Using

https://www4c.receita.fazenda.gov.br/carga-web/EmitirExtratoEscalaMenu.do?nrEscala=09000375571 {the number will change each time}

HTML code below

<FORM method=post name=EmitirExtratoEscalaForm action=/carga-web/EmitirExtratoEscala.do>

<INPUT value=true type=hidden name=voltarInicioFuncao _png_class>

<FIELDSET>

<P><LABEL for=nrEscala>Número da Escala : </LABEL>

<INPUT class=txtgeral onkeyup="return VerifyENTERPressed(this,event)" value=09000375571 maxLength=11 size=14 name=nrEscala _png_class="txtgeral">

</P>

</FIELDSET>

<P class=botoes><IMG style="CURSOR: hand" onmouseover="javascript:this.src='./images/pt_BR/enviar_ov.gif';this.style.cursor='hand'" onmouseout="javascript:this.src='./images/pt_BR/enviar.gif';" onclick="document.forms['EmitirExtratoEscalaForm'].submit()" name=enviar src="./images/pt_BR/enviar.gif" _png_class> &nbsp;&nbsp; <IMG style="CURSOR: hand" onmouseover="javascript:this.src='./images/pt_BR/limpar_ov.gif';this.style.cursor='hand'" onmouseout="javascript:this.src='./images/pt_BR/limpar.gif';" onclick=javascript:limparCampos(); border=0 src="./images/pt_BR/limpar.gif" _png_class>

</P>

</FORM>

The result when I submit is a file to download with the name: relatorioEscala.pdf (Alwas same name)