function validate_email(email){
  padrao = /\b[A-Z0-9._%+-]+@(?:[A-Z0-9-]+\.)+[A-Z]{2,4}\b/gi;
  test = padrao.exec(email);
  if(test){
  return true;
  }
  return false;
}

function show_modelo(){
    $("#modelo").attr("disabled","");
}
function hide_modelo(){
    $("#modelo").attr("disabled","disabled");
}