JS Modal- Not using Bootstrap

Question

How do I use an anchor tag instead of a button to trigger the modal? I can't use Bootstrap because I need to modify the size of the modal. I tried putting the ID in the href but that didn't help. Any suggestions?

// Get the modal
var modal = document.getElementById('myModal');

// Get the button that opens the modal
var btn = document.getElementById("myBtn");

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

// When the user clicks the button, open the modal 
btn.onclick = function() {
    modal.style.display = "block";
}

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

// When the user clicks anywhere outside of the modal, close it
window.onclick = function(event) {
    if (event.target == modal) {
        modal.style.display = "none";
    }
}

<!-- Trigger/Open The Modal -->
<button id="myBtn">Open Modal</button>

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

  <!-- Modal content -->
  <div class="modal-content">
    <div class="modal-header">
      <span class="close">&times;</span>
      <h2>Modal Header</h2>
    </div>
    <div class="modal-body">
      <p>Some text in the Modal Body</p>
     
    </div>
    <div class="modal-footer">
      <h3>Modal Footer</h3>
    </div>
  </div>

</div>

Answer 1

If you simply change the existing <button> tag to <a> then your existing JS code should work. The principle is exactly the same, to get a reference to the element by ID and then attach a click handler.

But to get the anchor to display as a link it needs an href, so I've used href="#", and then updated the click function to cancel the default click behaviour.

You probably also want some CSS to hide the modal initially.

// Get the modal
var modal = document.getElementById('myModal');

// Get the button that opens the modal
var btn = document.getElementById("myBtn");

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

// When the user clicks the button, open the modal 
btn.onclick = function(e) {
    e.preventDefault();  // ADDED this line
    modal.style.display = "block";
}

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

// When the user clicks anywhere outside of the modal, close it
window.onclick = function(event) {
    if (event.target == modal) {
        modal.style.display = "none";
    }
}

#myModal { display: none; }  /* added this CSS */

<!-- Trigger/Open The Modal -->
<a id="myBtn" href="#">Open Modal</a>  <!-- changed tags, added href, kept id -->

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

  <!-- Modal content -->
  <div class="modal-content">
    <div class="modal-header">
      <span class="close">&times;</span>
      <h2>Modal Header</h2>
    </div>
    <div class="modal-body">
      <p>Some text in the Modal Body</p>
     
    </div>
    <div class="modal-footer">
      <h3>Modal Footer</h3>
    </div>
  </div>

</div>