 <p><code>&lt;?AdlibExpress...?&gt;</code> is a <a href="https://en.wikipedia.org/wiki/Processing_Instruction" rel="nofollow">processing instruction</a>.</p> <p>You can create it with </p> <pre><code>doc.appendChild( doc.createProcessingInstruction("AdlibExpress", "applanguage=\"USA\" appversion=\"5.0.0\" dtdversion=\"2.6.3\"")); </code></pre>