I've been trying to pass textbox input value

<input type="text" class="form-control" name="XField" id="XField" placeholder="X">

that was edited via javascript like document.getElementById("XField").value = '1' to the controller by calling $this->input->post('XField') or even using $_POST, but it wont return anything. it's like $this->input->post('XField') will only get the user inputted value, not the manually edited value via js because all my other textbox input value that was inputted by user got properly extracted by $this->input->post('XField') or $_POST. I also already tried using $('#XField').val(1) but still wont get me anything.

So, How do i get the manually defined/edited value of input textbox from the view to the controller?or how do i manually define/edit the textbox value as if it was coming from the user(if my assumption is true that input post wont catch manually edited value)?