JSFiddle - React, Tailwind, and code Playground

HTML

<img src="/images/info_icon.gif" class="tooltip_icon" alt="sample">
<div class="tooltip_modal">
  <div class="modal-content">
    <div class="modal-header">
      <span class="close">&times;</span>
      <h5>Tooltip</h5>
    </div>
    <div class="modal-body">
      <p>Sample text one</p>
    </div>
  </div>
</div>

<img src="/images/info_icon.gif" class="tooltip_icon" alt="sample">
<div class="tooltip_modal">
  <div class="modal-content">
    <div class="modal-header">
      <span class="close">&times;</span>
      <h5>Tooltip</h5>
    </div>
    <div class="modal-body">
      <p>Sample text 2</p>
    </div>
  </div>
</div>

<img src="/images/info_icon.gif" class="tooltip_icon" alt="sample">
<div class="tooltip_modal">
  <div class="modal-content">
    <div class="modal-header">
      <span class="close">&times;</span>
      <h5>Tooltip</h5>
    </div>
    <div class="modal-body">
      <p>Some text 3</p>
    </div>
  </div>
</div>

CSS

/* The Modal (background) */
.tooltip_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(0,0,0,0.4); /* Black w/ opacity */
}

/* Modal Content */
.modal-content {
    position: relative;
    background-color: #fefefe;
    margin: auto;
    padding: 0;
    border: 1px solid #888;
    width: 80%;
    box-shadow: 0 4px 8px 0 rgba(0,0,0,0.2),0 6px 20px 0 rgba(0,0,0,0.19);
    -webkit-animation-name: animatetop;
    -webkit-animation-duration: 0.4s;
    animation-name: animatetop;
    animation-duration: 0.4s
}

/* Add Animation */
@-webkit-keyframes animatetop {
    from {top:-300px; opacity:0} 
    to {top:0; opacity:1}
}

@keyframes animatetop {
    from {top:-300px; opacity:0}
    to {top:0; opacity:1}
}

/* The Close Button */
.close {
    color: white;
    float: right;
    font-size: 28px;
    font-weight: bold;
}

.close:hover,
.close:focus {
    color: #000;
    text-decoration: none;
    cursor: pointer;
}

.modal-header {
    padding: 2px 16px;
    background-color: #425563;
    border-bottom: 4px solid #ffd100;
    color: white;
}

.modal-body {padding: 10px 16px;}

.modal-footer {
    padding: 2px 16px;
    background-color: #5cb85c;
    color: white;
}

/* Tooltip icon*/
.tooltip_icon
    {
        padding-bottom: 4px;
        padding-left: 2px;
    }

JavaScript

var btn = document.getElementsByClassName("tooltip_icon");
var modal = document.getElementsByClassName("tooltip_modal");


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

// When the user clicks the button, open the modal 
function displayModal(k) {
    modal[k].style.display = "block";
}

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

for (var i=0,j=0; i<btn.length,j<modal.length; i++,j++) {

    btn[i].onclick = displayModal(j);
    span.onclick = hideModal(j);
    window.onclick = function(event) {
    if (event.target == modal[j]) {
        hideModal(j);
    }
}
}



// When the user clicks anywhere outside of the modal, close it