I am using the following code to retrieve a file from the server so the client can download it. Is there any way I can find out which files have been downloaded? Maybe if a text file could be stored somewhere which could keep on adding filenames as they are downloaded are accessed?

function downloadPdf(){    

//fetch the registrationId from the input#url
let registrationId = document.getElementById("url").value;        

//transform the registrationId string to lower case
registrationId = registrationId.trim().toLowerCase();

const pdfUrl = `/ooecertificate/${registrationId}.pdf`;        

//this is the statement to redirect the browser to the wanted url
//now commented because it wouldn't work here on the snippet

//window.location.href = pdfUrl;

//on its behalf I'm writing the url on console
console.log(pdfUrl); }

label.fieldLabel{
  display: block;
  margin-bottom: 1rem;
}

label.fieldDescription{
  display: block;
  margin-bottom: 1rem;   
  border: solid 1px gray;
  padding: 1em;
}

button{
  cursor: pointer;
}

<div>
  <label class="fieldDescription">
  Your registration id is your firstname+registered email id:<br>
  For example..<br>
  if your name is SAMMY DIXIT and your registered email id is SAMMY.DIXIT@GMAIL.COM<br>
  your REGISTRATION ID WILL BE: <b>sammysammy.dixit@gmail.com</b>
  </label> 

  <label class="fieldLabel">ENTER YOUR REGISTRATION ID:</label>   

  <input type="text" name="url" id="url"> 

  <button onclick="downloadPdf();">Download</button>
  
</div>