I just need a pop up or a message saying 'thank you for submiting', but the onclick button to confirm is making that hard to do it
<div class="container">
<form action="https://webto.salesforce.com/servlet/servlet.WebToLead?encoding=UTF-8" method="POST" onsubmit="Obrigada">
<input type="hidden" name="oid" value="00D200000005V5n">
<input type="hidden" name="retURL" value="O email foi enviado com sucesso">
<input type="hidden" name="00N20000002ePlc" value="eAccounting">
<input type="hidden" name="lead_source" value="Other">
<input type="hidden" name="Lead_Origin__c" value="Other">
<input type="hidden" name="Nome_Origem_Lista__c" value="http://doc.saphety.com/site/files/mktdepot/Forms/pt/Form_Petapilot.html">
<div>
<label for="last_name">*Nome do Utilizador:<span class="required"> </span></label>
<textarea id="last_name" name="last_name" class="inputField" required></textarea>
</div>
<div>
<label for="email">*E-Mail: <span class="required"> </span></label>
<input id="email" maxlength="80" name="email" size="20" type="email" pattern="[a-z0-9._%+-]+@[a-z0-9.-]+.[a-z]{2,63}$" /><br>
</div>
<div>
<label for="Password__c">*Password:<span class="required"> </span></label>
<textarea id="Password__c" name="Password__c" class="inputField" required></textarea>
</div>
<div>
<label for="Agent__c">*Responsável pelo pedido:<span class="required"> </span></label>
<textarea id="Agent__c" name="Agent__c" class="inputField" required></textarea>
</div>
<div>
<label for="description">Descrição:<span class=""> </span></label>
<textarea id="description" name="description" class="inputField"></textarea>
</div>
<p></p>
<div class="divActions">
<span onclick="Alertasubmissao();">
</span>
<input type="submit" name="submit" value="ENVIAR" onclick="return confirm('Tem a certeza que deseja enviar os dados ao cliente?');">You haven't written it in Javascript code and it's pretty difficult and gets your code messy if you trying to do it within HTML. It's better to make another file which is called for example: submitting.js and refer to it when clicked on the button.
<input type="submit" name="submit" value="ENVIAR" onclick="submitting.js">
In the submitting.js you should include the alert function of 'Javascript'. For example like this:
<script type="text/javascript">
alert("You have clicked the button!");
</script>
i hope this will help you, you need to move your confirmation and alert into a single function and call it when the form is submitted
if the user hit no to confirm Dialogue the form submission will be cancelled and if user hit confirm the form will be submitted and out thank you alert will be displayed.
document.querySelector('form').onsubmit = (e)=>{
let okToSubmit = confirm('Tem a certeza que deseja enviar os dados ao cliente?');
if(!okToSubmit) return false
document.querySelector('.alert').innerText = "Thank you for submitting";
return true;
}<form action="/" method="post">
<input type="text" name="name">
<input type="submit"/>
</form>
<div class="alert"></div>