findElement()
html <- '<div id="form">
<form accept-charset="utf-8" method="POST" novalidate="">
<div class="form-group"><label for="form_Name" class="control-label">Full name<sup>*</sup></label><input required="" pattern="^***+(.****" class="form-control" title="Full name" id="form_Name" type="text" name="form_Name"></div>
<div class="form-group"><label for="form_Email" class="control-label">Email address<sup>*</sup></label><input required="" class="form-control" title="Email address" id="form_Email" type="email" name="form_Email"></div>
<div class="form-group"><label for="form_Company" class="control-label">Company name<sup>*</sup></label><input class="form-control" title="Company name" required="" id="form_Company" type="text" name="form_Company"></div>
<div class="form-group"><label for="custom_Message" class="control-label">Message</label><textarea class="form-control" title="Message" id="custom_Message" name="custom_Message"></textarea></div>
<div><input class="btn-large btn-inverse btn" type="submit" value="Submit"></div>
</form>
</div>
'
tmp <- tempfile(fileext = ".html")
cat(html, file = tmp)
RSelenium
library(RSelenium)
rD <- rsDriver()
remDr <- rD[["client"]]
remDr$navigate(paste0("file://", tmp))
# Find and populate the field
webElem <- remDr$findElement(using = "id", "form_Name")
webElem$sendKeysToElement(list("Foo Bar"))
# Close browser
remDr$close()
https://ropensci.org/tutorials/rselenium_tutorial/