a javascript function only works once on page

Question

I am trying to use this example to create modal pop ups for image: https://www.w3schools.com/howto/howto_css_modal_images.asp

I have most everything working as needed however I can not seem to make it work more than once on the same page.

I am generating file lists in php and that is sure to complicate it too.

There is a try it editor of this code here https://www.w3schools.com/howto/tryit.asp?filename=tryhow_css_modal_img

ultimately I need this to wrap around my links generated in PHP.

  // 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.getElementById('myImg'); var modalImg = document.getElementById("img01"); 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"; } 

  body {font-family: Arial, Helvetica, sans-serif;} #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 */ #caption { margin: auto; display: block; width: 80%; max-width: 700px; text-align: center; color: #ccc; padding: 10px 0; height: 150px; } /* Add Animation */ .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%; } } 

  <img id="myImg" src="img_snow.jpg" alt="Snow" style="width:100%; max-width:300px"> <!-- The Modal --> <div id="myModal" class="modal"> <span class="close">&times;</span> <img class="modal-content" id="img01"> <div id="caption"></div> </div> 

Answer 1

If we want to be able to click on multiple images we can add a class to all your images (in the example below : js-img ). Thanks to that class you can query back those elements and loop over each to add a onclick listener.

We can see here a working example : https://jsfiddle.net/k8woxf0s/3/

Main code is (loop) :

Array.from(imgs).forEach(function(img) {
  img.onclick = function() {
    modal.style.display = "block";
    modalImg.src = this.src;
    captionText.innerHTML = this.alt;
  };
})

Array.from is necessary because getElementsByClassName do not return an array but a HTMLCollection : https://developer.mozilla.org/en-US/docs/Web/API/Document/getElementsByClassName .

You can use querySelectorAll (which is a more recent function), see here : https://developer.mozilla.org/en-US/docs/Web/API/Document/querySelectorAll

Now you have to write the code to generate the DOM for your images (PHP code).

Hope that it helps you :).