title: Prototypejs observe function throws error
body: <p>I have this line of code but it throws an error.  What is the problem with the code?</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;html&gt;
      &lt;head&gt;
          &lt;script src="http://prototypejs.org/javascripts/prototype.js" type="text/javascript"&gt;&lt;/script&gt;
          &lt;script type="text/javascript"&gt;
  
              Event.observe('target', 'click', function(event) {
                  // ...
              });
  
          &lt;/script&gt;   
      &lt;/head&gt;
      &lt;body&gt;
          &lt;p id='target'&gt;Click me!&lt;/p&gt;
      &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>