R: web scrapping with inputs and results on a new pop-up

Hi I am doing a lot of DNA sequence conversions through this webpage (http://www.bioinformatics.org/sms2/rev_comp.html).

I will need to input some sequence to the input textbox and then click the Submit button.

Once I click the Submit button, a pop up window will come out and have some text(transformed sequence) that I then want to save (see below as an example).

As I need to do thousand of them, could someone suggest how i could do it in R and save the output in a dataframe? Thanks!

INPUT to the textbox:

>Sample sequence 1
garkbdctymvhu

OUTPUT in the pop up:

Reverse Complement results

>Sample sequence 1 reverse complement
adbkraghvmytc