Hello I'm trying to include in a modal a custom form (is not a BizKentico Form) when it is rendered the tag <form>
is missing and when click submit buttom it realod the page and lose de input data before.
Are you using Portal engine or MVC? If you are using Portal, Kentico wraps the entire page in a form tag. You can hack it buy doing something like this, but it may cause some issues on the page.
</form>
<form>
your form data
</form>
<form>