HTML code not working on WIX Widget

Hello,

I have recently been in contact with WIX who seem to not be able to answer my question regarding adding HTML code onto WIX. I am very new to coding and have been provided with code from another company to add to my WIX website which will allow students to access online classrooms which I teach on.

The code seemed to be working fine for 5 minutes yesterday however then stopped working and now when I enter my log in details and password the screen simply goes blank. The HTML provider has told me that the reason for this is due to WIX embedding the logon code snippet into an IFRAME element which is not permitted in many web browsers and that's why it is not working properly.

Apparently in order for the code to work the HTML needs to be pure, I have been advised to try and enter this directly into WIX code however I have absolutely no idea how this works and where to even start.

Please see below the code in which I have been provided with and my website page ( the HTML input is underneath the class tab). I have also attached an image given to me by the HTML providers explaining the issue. I would really appreciate some help on this issue as I have been struggling to understand it over the past few days and it is very important to the website.

<!-- BEGIN ELECTA LIVE LOGIN FORM -->

<script language="javascript">

function signin(AUserID, APassword) {

var d = new Date();

document.electalogin.timezone.value = d.getTimezoneOffset();

if (AUserID == "" || APassword == "") {

window.alert ("Please Specify Your Username and Password") }

return ( AUserID && APassword ? true : false);}

</script>

<form method="post" action="https://Maths4U.school-network.net/Account/HTMLLogon" id="electalogin" name="electalogin" LANGUAGE="javascript" onsubmit="return signin(this.UserID.value, this.Password.value)">

<input type=hidden name="timezone">

<table>

<tr><td style="font-family:Tahoma; Font-Size:11px">Username</td><td><input name="username" value=""></td></tr>

<tr><td style="font-family:Tahoma; Font-Size:11px">Password</td><td><input type="password" name="Password"></td></tr>

<tr><td></td><td><a style="font-family:Tahoma; Font-Size:11px" target="_blank" href="https://Maths4U.school-network.net/Account/ForgotPassword">Lost Password?</a></td></tr>

<tr><td></td><td><INPUT type="Submit" value="Log On" id=btnLogin name=btnLogin></td></tr>

</table>

</form>

<!-- END ELECTA LIVE LOGIN FORM -->

Website Address: www.m4ths4u.com

Thank you in advance

Sophie