title: Error dropdown materialize using .dropdown() - $ is not a function
body: <p>I am triying to install a dropdown in materialize using instructions but when ran the code console throw me an error</p>
  
  <p>This is the code</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>//main.js
  $(()=&gt;{ 
   alert("Hola de nuevo! Ahora con Materialize")
   console.log('Main cargando')
    $('.dropdown-button').dropdown();
  
  })</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;!DOCTYPE html&gt;
  &lt;html lang="en"&gt;
  &lt;head&gt;
   &lt;meta charset="UTF-8"&gt;
   &lt;title&gt;Ejs Test&lt;/title&gt;
   &lt;link rel="stylesheet" href="css/materialize.css"&gt;
   &lt;link rel="stylesheet" href="css/materialize.min.css"&gt;
    
  
   &lt;script src="js/materialize.min.js"&gt;&lt;/script&gt;
   &lt;script src="js/jquery.js"&gt;&lt;/script&gt;
   &lt;script src="js/main.js"&gt;&lt;/script&gt;
  
  &lt;/head&gt;
  &lt;body&gt;
  
   &lt;ul class="dropdown-content" id="dropdown1"&gt;
    &lt;li&gt;TextoPrueba&lt;/li&gt;
    &lt;li&gt;TextoPrueba&lt;/li&gt;
    &lt;li&gt;TextoPrueba&lt;/li&gt;
   &lt;/ul&gt; 
   &lt;div class="navbar-fixed"&gt;
    &lt;nav&gt;
     &lt;div class="nav-wrapper"&gt;
      &lt;a href="#" class="brand-logo"&gt;BrandLogo&lt;/a&gt;
      &lt;ul class="right hide-on-med-and-down"&gt;
       &lt;li&gt;&lt;a href="#"&gt;Texto1&lt;/a&gt;&lt;/li&gt;
       &lt;li&gt;&lt;a href="#"&gt;Texto2&lt;/a&gt;&lt;/li&gt;
       &lt;li&gt;&lt;a href="#"&gt;Texto3&lt;/a&gt;&lt;/li&gt;
       &lt;li&gt;&lt;a href="#" class="dropdown-button" data-activates="dropdown1"&gt;TextoDropDown&lt;/a&gt;&lt;/li&gt;
      &lt;/ul&gt;
     &lt;/div&gt;
    &lt;/nav&gt;
   &lt;/div&gt;
  &lt;/body&gt;
  &lt;/html&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>in the  console of the code inspector throw me </p>
  
  <p>Uncaught TypeError: $(...).dropdown is not a function</p>
  
  <p>what can i do to show the dropdown correctly?</p>