Auto input hidden value

I am trying to make a custom unsubscribe page (in pardot), I used the inspect tool and grabbed the current HTML code, I’m running into an issue with the input field, this is what the code currently looks like:

<input type="text" name="piEmailPrefEmail" id="piEmailPrefEmail"
 value="m******s@t*****x.com" class="text" readonly="readonly" >

The value needs to change so that it is not my email. Ideally I would like it to pull the users email the same way it does mine, with the hidden characters. Not sure what I need to update in the HTML and or what javascript code needs to be added.

I tried removing my email address and leaving the value field blank, which works when I remove “readonly” but ideally the user will not need to put in their own email address.