title: Show/hide image with JavaScript
body: <p>I have an HTML page with an image that I set to be invisible by CSS <code>visibility: hidden</code>. I want to make a link called "Show image", so that when I click on it, the image appears. </p>
  
  <p>Now, I don't know how to make such a link, since normally a link with <code>&lt;a href=...&gt;</code> links to some other page. In my case, I want the link to invoke a JavaScript to display the image.</p>