credentialless="false" -> .credentialless true

by David Iglesias

HTML

<iframe credentialless="false" src="about:blank" id="credentiallessIframe"></iframe>

<p>Credentialless? <span id="isCredentialless"></span></p>

CSS

iframe {
  width: 20px; height: 20px;
}

JavaScript

let credentialless = credentiallessIframe.credentialless;

isCredentialless.innerText = credentialless ? 'Yes' : 'No!';