Click on the solution, please. Through curl I send post and I receive the answer from a site. It has hidden fields that the server checks for emptiness. I get the answer and put it in the iframe (myself), I look at the source: the fields with type = "text" are filled, and hidden is not.
Although through the post I sent all the data. It is important for me that they are filled. As the server swears.
How can I change the value hidden.