title: How to simulate a mouse click on an <a> tag that has no href?
body: <p>I want to use a userscript to automatically click on a button when a page is loaded.<br>
  The target page's HTML (which I do not control) looks like this:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;a id="signInBtn" alog-alias="qb-signin-btn" class="signInBefore btn btn-24-white grid" data-disabled="false" hidefocus="hidefocus"&gt;
      &lt;em&gt;&lt;b&gt;CheckIn&lt;/b&gt;&lt;/em&gt;
  &lt;/a&gt;
  </code></pre>
  
  <p>It is a strange link without an <code>href</code> attribute. I am trying to use this code:</p>
  
  <pre><code>var btn = $("a#signInBtn");
  btn.trigger("click");
  </code></pre>
  
  <p>But Chrome's console gives me this:</p>
  
  <blockquote>
    <p>Error in event handler for (unknown):<br>
    Error: Syntax error, unrecognized expression: a[href^=/i?]</p>
  </blockquote>
  
  <p>How can my userscript click this button?</p>