Hello,
I'm studying ASP.NET Web Forms at my school and I'm trying to add a login modal to my project.

I'm following the tutorial from W3Schools and it seems to work fine but as soon as I replace the inputs with asp inputs (HTML input textbox to asp.net textbox...) and remove the "required" parameters the modal closes within miliseconds of opening it.

I've done some tests and it appears that it only happens when the HTML part of the modal is placed within the <form runat="server"> part.

Also, it's worth noting that I am aware of the fact that forms cannot be nested in a web forms form. Thus, I've changed

<form class="modal-content animate" action="/action_page.php">

to

<div class="modal-content animate">

My question is - why is it happening and what can I do to solve this issue? Thanks in advance.