How to perform a login identification process in the best way? - asp.net-mvc

Question

I have 2 inputs boxes: Public key (user name) and Private key (password). Also I have a hidden warning label.
This is my code (and it's perfectly working ):
<script language="javascript">
function SendLoginData() {
document.getElementById("LoginErrorLabel").style.display = "none";
var url = "/DappAccount/CheckAccount";
$.post(url, { PublicKey: $("#public_key_input").val(), PrivateKey: $("#private_key_input").val() }, function (data) {
if (data == false) {
document.getElementById("LoginErrorLabel").style.display = "block";
return;
}
else {
document.getElementById("loader").style.display = "block";
$("#myform").submit()
}
});
}
</script>
<div class="container">
#using (Html.BeginForm("AccountMainPage", "DappAccount", FormMethod.Post, new { #id = "myform" }))
{
<div class="row justify-content-center">
#Html.TextBoxFor(m => m.publicKey, new { id = "public_key_input", placeholder = "Ethereum Public Key", required = "required" })
</div> <br />
<div class="row justify-content-center">
#Html.TextBoxFor(m => m.privateKey, new { id = "private_key_input", placeholder = "Ethereum Private Key", required = "required", type = "password" })
</div> <br />
<div class="row justify-content-center">
<img id="loader" style="display: none;" src="https://s5.gifyu.com/images/Loader5a73d3b26568dbc4.gif" alt="Loader5a73d3b26568dbc4.gif" border="0" />
</div> <br />
}
<div class="row justify-content-center">
<input id="submit" type="button" value="Login" class="btn btn-primary" onclick="SendLoginData()" />
</div>
<label id="LoginErrorLabel" style="color: red; display: none;">*Wrong login detail !</label>
</div>
What I'm doing here is:
1) Send username&password to the 'CheckAccount' method in the controller, the method returns true/false.
2) If false, show label,
if true, show gif image and send again the details to ActionResult (=AccountMainPage) which returns a new view.
I just wonder, is there a better/shorter way to do it using one post or one method? I heard something about the partial views in MVC, no idea what to do with it. People told me that what I did here is too old for MVC