I am currently trying to make multiple images which when click will have different pictures

I used the code here: here:

CodePudding user response：

id must be unique for every img tag you can get id from onClick event.

function modal_open(clicked_id)
  {
     var modal = document.getElementById("myModal");

    var img = document.getElementById(clicked_id);
    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:0px auto;
  display: block;
  width: 100%;
  max-width: 900px;
}

/* Caption of Modal Image */
#caption {
  margin: auto;
  display: block;
  width: 80%;
  max-width: 700px;
  text-align: center;
  color: #ccc;
  padding: 10px 0;
  height: 200px;
}

/* 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%;
  }
}

<!-- Trigger the Modal -->
<img id="myImg" src="https://www.w3schools.com/howto/img_nature.jpg" alt="Snow" style="width:100%;max-width:300px" onm ouseover="modal_open(this.id)">
<img id="myImg1" src="https://www.w3schools.com/howto/img_lights.jpg" alt="Snow" style="width:100%;max-width:300px" onm ouseover="modal_open(this.id)">

<!-- The Modal -->
<div id="myModal" >
  <span >&times;</span>
  <img  id="img01">
  <div id="caption"></div>
</div>

CodePudding user response：

Your error is because the onclick function attempting to assign the url to src of the <img> element that "suppose" comes with the ID img01, but the html doesn't have the <img> with the id.

Refer to @Robin Hood answer, his code explains the proper way of implementation.