I asked another question here in the forum about another subject that helped me a lot about this however the link opens in a new page.
What I would like is that by clicking on the submit it would open inside an iframe inside the page and if the field was not filled it would receive a popup saying that the field was not filled ..
<?php
if (isset($_REQUEST['txt_url'])) {
$link = 'http://' . $_REQUEST['txt_url'] . '.datatix.com.br';
header('Location: ' . $link);
}
?>
<div class="instancia">
<div class="content">
<img src="img/logo_datatix.jpg" height="32px">
<form action="" method="post">
<input type="text" name="txt_url" value="" placeholder="Digite sua Instância">
<input type="submit" value="Ok" name="ok "class="ok">
</form>
</div>
</div>
<div class="iframe">
<iframe id="conteudo_iframe"></iframe>
</div>
If possible do not use php would be much better.
It would be more or less what is in the code below, but the user does not put the entire domain just the subdomain.
Example: It puts "test" and "OK" but in the iframe it would load the link test.domain.com
body{ padding:0; margin:0;}
.instancia{ background-color:#D3172F; color:#FFF; font-family:Segoe, "Segoe UI", "DejaVu Sans", "Trebuchet MS", Verdana, sans-serif; width:100%; position:fixed; border-bottom:#9B1022 2px solid !important;}
.instancia .content{ width:320px; margin:0 auto; display:table;}
.instancia img{ float: left;}
.instancia input{ height:30px; padding-left:5px; padding-right:5px; width:176px; border:0; float: left;}
.instancia .ok{ border:0; background-color:#9B1022; height:32px; width:32px; color:#FFF; float:left; font-weight:bold; cursor:pointer;}
<div class="instancia">
<div class="content">
<img src="img/logo.jpg" height="32px">
<form action="" method="post">
<input type="text" name="txt_url" value="" placeholder="Digite sua Instância">
<input type="submit" value="Ok" name="ok "class="ok">
</form>
</div>
</div>
<div class="iframe">
<iframe name="exemplo" width="100%"></iframe>
</div>