How to parse first part of entered email address and save as a new embedded data element

I have participants entering their email address in a text field on a single page survey. I want to take the part that appears before the @ in the email address and assign it to a new embedded data variable.

For example, if I entered jonese@ email.com (extra space added after the @ to avoid linking to a fake email) in the text field, I would want to assign the string “jonese” to the embedded variable.

Here’s the code I have that isn’t working:

Qualtrics.SurveyEngine.addOnUnload(function()

{

    /*Place your JavaScript here to run when the page is unloaded*/

    

    var kkiEmail = "${q://QID12/ChoiceTextEntryValue}";  

    var getUsername = kkiEmail.split("@"); 

    Qualtrics.SurveyEngine.setEmbeddedData("username",getUsername[0]); 

});

Any suggested JavaScript syntax and guidance on where it should be placed would be greatly appreciated!

Thanks!
Erin