title: JavaScript Calculator using HTML forms
body: <p>I want to create a calculator that, using JavaScript, takes a number from an HTML input box like this one. </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>// Take form input and multiply by four</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
    &lt;head&gt;
    &lt;/head&gt;
    &lt;body&gt;
      &lt;input placeholder="Side Length of Square"/&gt;
    &lt;/body&gt;  
  &lt;/html&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>How could I then relay the user input, say 5, so that the JavaScript would take "5" and multiply it to find the area of the square? This is my first question ever on Stack Overflow, so I apologize if I did something wrong. Thanks for the help!</p>