Modal image galleries - multiple images

I am currently trying to make an image gallery based on the code here: http://www.w3schools.com/howto/howto_css_modal_images.asp

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.

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

Thanks! :)

Here's the HTML and javascript from the body of my code.

    <div class="container" id="gallery">

        <h1>Gallery</h1>

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

        <!-- The Modal -->
        <div id="myModal" class="modal">

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

          <!-- Modal Content (The Image) -->
          <img class="modal-content" id="modal-image">

          <!-- Modal Caption (Image Text) -->
          <div id="caption"></div>
        </div>

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

        <!-- The Modal -->
        <div id="myModal" class="modal">

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

          <!-- Modal Content (The Image) -->
          <img class="modal-content" id="modal-image">

          <!-- Modal Caption (Image Text) -->
          <div id="caption"></div>
        </div>

    </div>


 <script>
    // 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 <span> element that closes the modal
    var span = document.getElementsByClassName("close")[0];

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

Solution 1:

Try this. It uses a little bit of jquery, but you don't have to change your html. except changing id="myImg" to class="myImg"

// 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 = $('.myImg');
var modalImg = $("#img01");
var captionText = document.getElementById("caption");
$('.myImg').click(function(){
    modal.style.display = "block";
    var newSrc = this.src;
    modalImg.attr('src', newSrc);
    captionText.innerHTML = this.alt;
});

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

// When the user clicks on <span> (x), close the modal
span.onclick = function() {
  modal.style.display = "none";
}
 /* Style the Image Used to Trigger the Modal */
.myImg {
    border-radius: 5px;
    cursor: pointer;
    transition: 0.3s;
}

.myImg:hover {opacity: 0.7;}

/* The Modal (background) */
.modal {
    display: none; /* Hidden by default */
    position: fixed; /* Stay in place */
    z-index: 1; /* Sit on top */
    padding-top: 100px; /* Location of the box */
    left: 0;
    top: 0;
    width: 100%; /* Full width */
    height: 100%; /* Full height */
    overflow: auto; /* Enable scroll if needed */
    background-color: rgb(0,0,0); /* Fallback color */
    background-color: rgba(0,0,0,0.9); /* Black w/ opacity */
}

/* Modal Content (Image) */
.modal-content {
    margin: auto;
    display: block;
    width: 80%;
    max-width: 700px;
}

/* Caption of Modal Image (Image Text) - Same Width as the Image */
#caption {
    margin: auto;
    display: block;
    width: 80%;
    max-width: 700px;
    text-align: center;
    color: #ccc;
    padding: 10px 0;
    height: 150px;
}

/* Add Animation - Zoom in the Modal */
.modal-content, #caption {
    -webkit-animation-name: zoom;
    -webkit-animation-duration: 0.6s;
    animation-name: zoom;
    animation-duration: 0.6s;
}

@-webkit-keyframes zoom {
    from {-webkit-transform:scale(0)}
    to {-webkit-transform:scale(1)}
}

@keyframes zoom {
    from {transform:scale(0)}
    to {transform:scale(1)}
}

/* The Close Button */
.close {
    position: absolute;
    top: 15px;
    right: 35px;
    color: #f1f1f1;
    font-size: 40px;
    font-weight: bold;
    transition: 0.3s;
}

.close:hover,
.close:focus {
    color: #bbb;
    text-decoration: none;
    cursor: pointer;
}

/* 100% Image Width on Smaller Screens */
@media only screen and (max-width: 700px){
    .modal-content {
        width: 100%;
    }
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<!-- Trigger the Modal -->
<img class="myImg" src="http://www.chinabuddhismencyclopedia.com/en/images/thumb/b/b8/Nature.jpg/240px-Nature.jpg" alt="Trolltunga, Norway" width="300" height="200">
<img class="myImg" src="http://www.worldlandtrust.org/sites/default/files/rainforest-reserve-regua-brazil.jpg" alt="Trolltunga, Norway" width="300" height="200">


<!-- The Modal -->
<div id="myModal" class="modal">

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

  <!-- Modal Content (The Image) -->
  <img class="modal-content" id="img01">

  <!-- Modal Caption (Image Text) -->
  <div id="caption"></div>
</div>

Solution 2:

Use only one Image-Modal block,and use that modal block to different images,all the images must have the same className(in this example "myImg"),and add following javascript. I hope this is helpful.

var modal = document.getElementById("myModal");
var i;

var img = document.getElementsByClassName("myImg");
var modalImg = document.getElementById("img01");

 for(i=0;i< img.length;i++)
   {    
    img[i].onclick = function(){

    modal.style.display = "block";
       modalImg.src = this.src;

 }
}

var span = document.getElementsByClassName("close")[0];


span.onclick = function() { 
   modal.style.display = "none";
}