title: How to detect mouse click when using Userscripts?
body: <p>I tried to add some functions to some websites I use everyday. I want to add a function that will remove some element when I click on certain links. So I use <em>Tampermonkey</em> and tried to test the following code:</p>
  
  <pre><code>function removeSth(){
  
      $('a').click(function(){
          alert ("warning");
          return false;
      });
  }
  removeSth();
  </code></pre>
  
  <p>Sadly, it doesn't work. This is what it says:</p>
  
  <blockquote>
    <p>ReferenceError: $ is not defined</p>
    
    <p>at removeUsers (eval at  (eval at eventHandler (eval at <code>&lt;anonymous&gt;</code>
    (chrome-extension://dhdgffkkebhmkfjojejmpbldmpobfkfo/content.js:56:21))),
    <code>&lt;anonymous&gt;</code>:65:5)</p>
  </blockquote>
  
  <p>I have no idea what these mean, honestly.</p>