HTML Code

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>srcdoc vs close stream</title>
  <style>body{font-family:system-ui,sans-serif;padding:1.5rem;} iframe{width:100%;height:100px;border:1px solid #ccc;margin:0.5rem 0;} pre{border:1px solid #ccc;padding:0.75rem;}</style>
</head>
<body>
  <button id="stream">Legacy: open / write / close</button>
  <button id="modern">Modern: srcdoc</button>
  <iframe id="preview" title="Preview"></iframe>
  <pre id="out">Choose a method</pre>
  <script>
    var iframe = document.getElementById("preview");
    var out = document.getElementById("out");
    document.getElementById("stream").addEventListener("click", function () {
      var doc = iframe.contentDocument;
      doc.open();
      doc.write("<p>Hello via document.write + close</p>");
      doc.close();
      out.textContent = "Used open / write / close";
    });
    document.getElementById("modern").addEventListener("click", function () {
      iframe.srcdoc = "<!DOCTYPE html><p>Hello without document.write</p>";
      out.textContent = "Used iframe.srcdoc (no close() needed)";
    });
  </script>
</body>
</html>

Lines: 0 | Characters: 0

Live Preview Auto-refresh on Run

Document.close — modern srcdoc alternative (Try It)