RegExp to match comma separated hostnames

Question

The problem

I\'m trying to validate the content of a </code> using JavaScript, So I created a <code>validate()</code> function, which returns <script async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script> <ins class="adsbygoogle" style="display:block" data-ad-client="ca-pub-5408099190056760" data-ad-slot="7305827575" data-ad-format="auto" data-full-width-responsive="true"></ins> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script> </div> </div> <div class="fly-panel detail-box" id="flyReply"> <fieldset class="layui-elem-field layui-field-title" style="text-align: center;"> <legend>6条回答</legend> </fieldset> <ul class="jieda" id="jieda"> <li data-id="111" class="jieda-daan"> <a name="item-1111111111"></a> <div class="detail-about detail-about-reply"> <a class="fly-avatar" href=""> <img src="https://www.e-learn.cn/qa/data/avatar/000/00/00/small_000000099.jpg" alt=" 忘掉有多难 "> </a> <div class="fly-detail-user"> <a href="" class="fly-link"> <cite> 忘掉有多难</cite> </a> <span>(楼主)</span> </div> <div class="detail-hits"> <span>2021-01-07 04:44</span> </div> </div> <div class="detail-body jieda-body photos"> <p> <p>An example with validate.js which has well tested routines for testing a valid FQDN. Alternatively look through the source and grab what you need.</p> <p><div class="snippet" data-lang="js" data-hide="false"> <div class="snippet-code"> <pre class="snippet-code-js lang-js prettyprint-override"><code>function validate (e) { var target = e.target || e; target.value.split(',').some(function (item) { var notValid = !validator.isFQDN(item.trim()); if (notValid) { target.classList.add('bad'); } else { target.classList.remove('bad'); } return notValid; }); } var domains = document.getElementById('domains'); domains.addEventListener('change', validate); validate(domains);</code></pre> <pre class="snippet-code-css lang-css prettyprint-override"><code>#domains { width: 300px; height: 100px; } .bad { background-color: red }</code></pre> <pre class="snippet-code-html lang-html prettyprint-override"><code><script src="http://rawgit.com/chriso/validator.js/master/validator.js"></script> <textarea id="domains">www.example.com, example.com, example.ca, example, example.com example.nl www.example, www.exam ple.com