Modal image galleries - multiple images
<p>I am currently trying to make an image gallery based on the code here: <a href="http://www.w3schools.com/howto/howto_css_modal_images.asp" rel="noreferrer">http://www.w3schools.com/howto/howto_css_modal_images.asp</a></p>

<p>This code works fine for a single image, however it doesn't work when you try and add more. I believe this has to do with the javascript using IDs, but when I try to use classes in place of IDs that code will not work.</p>

<p>Has anybody had any luck using this example from W3 Schools to create a working gallery?</p>

<p>Thanks! :)</p>

<p>Here's the HTML and javascript from the body of my code.</p>

<pre><code>    &lt;div class="container" id="gallery"&gt;

        &lt;h1&gt;Gallery&lt;/h1&gt;

        &lt;!-- Trigger the Modal --&gt;
        &lt;img id="thumbnail-01" class="myImg" src="images/thumbnail.jpg" alt="Trolltunga, Norway" width="300" height="200"&gt;

        &lt;!-- The Modal --&gt;
        &lt;div id="myModal" class="modal"&gt;

          &lt;!-- The Close Button --&gt;
          &lt;span class="close" onclick="document.getElementById('myModal').style.display='none'"&gt;&amp;times;&lt;/span&gt;

          &lt;!-- Modal Content (The Image) --&gt;
          &lt;img class="modal-content" id="modal-image"&gt;

          &lt;!-- Modal Caption (Image Text) --&gt;
          &lt;div id="caption"&gt;&lt;/div&gt;
        &lt;/div&gt;

        &lt;!-- Trigger the Modal --&gt;
        &lt;img id="thumbnail-02" class="myImg" src="images/thumbnail.jpg" alt="Trolltunga, Norway" width="300" height="200"&gt;

        &lt;!-- The Modal --&gt;
        &lt;div id="myModal" class="modal"&gt;

          &lt;!-- The Close Button --&gt;
          &lt;span class="close" onclick="document.getElementById('myModal').style.display='none'"&gt;&amp;times;&lt;/span&gt;

          &lt;!-- Modal Content (The Image) --&gt;
          &lt;img class="modal-content" id="modal-image"&gt;

          &lt;!-- Modal Caption (Image Text) --&gt;
          &lt;div id="caption"&gt;&lt;/div&gt;
        &lt;/div&gt;

    &lt;/div&gt;


 &lt;script&gt;
    // Get the modal
    var modal = document.getElementById('myModal');

    // Get the image and insert it inside the modal - use its "alt" text as a caption
    var img = document.getElementsByClassName('myImg');
    var modalImg = document.getElementById("modal-image");
    var captionText = document.getElementById("caption");
    img.onclick = function(){
        modal.style.display = "block";
        modalImg.src = this.src;
        captionText.innerHTML = this.alt;
    }

    // Get the &lt;span&gt; element that closes the modal
    var span = document.getElementsByClassName("close")[0];

    // When the user clicks on &lt;span&gt; (x), close the modal
    span.onclick = function() { 
      modal.style.display = "none";
    }
&lt;/script&gt;
</code></pre>