Rvest with fake submit

rvest_fake_submit.R

require(rvest)

#website
url <- ("http://www.anbima.com.br/est_termo/Curva_Zero.asp")
pgsession <- html_session(url)
pgform <-html_form(pgsession)[[1]]

fake_submit <- list("name" = NULL, 
                    "type" = "submit", 
                    "value" = "Submit", 
                    "checked" = NULL, 
                    "disabled" = NULL,
                    "readonly" = NULL,
                    "required" = FALSE)
attr(fake_submit, "class") <- "input"

pgform$fields$fake_submit <- fake_submit

param <- set_values(form = pgform, 
                    "escolha" = "2",
                    "Dt_Ref" = Sys.Date()
)

submit <- submit_form(pgsession, pgform)