Web-scraping popup table without submit button using R - css

Question

I'm trying to scrape zip codes from "https://www.zipcodestogo.com/county-zip-code-list.htm", where states and counties will be provided in a dataset. Take Alabama, Dale as an example (shown below). However, when I use Selector Gadget to extract the table it does not appear, and when I look at the source code I also don't find this table. I'm not sure how to solve this. I'm very new to web-scraping so I apologize in advance if this is a stupid question. Thank you.
zipurl = 'https://www.zipcodestogo.com/county-zip-code-list.htm'
query = list('State:'="Alabama",
'Counties:'="Dale"
)
website = POST(zipurl, body = query,encode = "form")
tables <- html_nodes(content(website), css = 'table')

Answer 1

Same idea but grabbing the table and removing header
library(rvest)
state = "ALABAMA"
county = "DALE"
url = paste0("https://www.zipcodestogo.com/lookups/countyZipCodes.php?state=",state,"&county=",county)
r <- read_html(url) %>%
html_node("table table") %>%
html_table()%>%
slice(-1)
print(r)
Zip codes only column is then:
r$X1
You could also limit to first table column and remove first row:
r <- read_html(url) %>%
html_nodes("table table td:nth-of-type(1)") %>%
html_text() %>%
as.character
print(r[-1])

Answer 2

You can use the links that you can find with your browser in Inspect > tab Network
Here a solution :
state = "ALABAMA"
county = "DALE"
url_scrape = paste0("https://www.zipcodestogo.com/lookups/countyZipCodes.php?state=",state,"&county=",county) # Inspect > Network > XHR links
# function => First letter Capital (needed for regexp)
capwords <- function(s, strict = T) { # You can find this function on the forum
cap <- function(s) paste(toupper(substring(s, 1, 1)),
{s <- substring(s, 2); if(strict) tolower(s) else s},
sep = "", collapse = " " )
sapply(strsplit(s, split = " "), cap, USE.NAMES = !is.null(names(s)))
}
zip_codes = read_html(url_scrape) %>% html_nodes("td") %>% html_text()
zip_codes = zip_codes[-c(1:6)] # Delete header
string_regexp = paste0(capwords(state),"|View") # pattern as var
zip_codes = zip_codes[-grep(pattern = string_regexp,zip_codes)]
df = data.frame(zip = zip_codes[grep("\\d",zip_codes)], label = zip_codes[-grep("\\d",zip_codes)])