.viewbox { display: none; position: fixed; z-index: 99999; padding-top: 100px; left: 0; top: 0; width: 100%; height: 100%; overflow: auto; background-color: rgb(0,0,0); background-color: rgba(0,0,0,0.4); } .viewbox-content { background-color: #fefefe; margin: auto; padding: 20px; border: 1px solid #525252; border-radius: 10px; width: 500px; } .close { color: #aaaaaa; float: right; font-size: 28px; font-weight: bold; } .close:hover, .close:focus { color: #000; text-decoration: none; cursor: pointer; } var modal = document.getElementById("popup"); var btn = document.getElementById("popupBtn"); var span = document.getElementsByClassName("close")[0]; btn.onclick = function() { modal.style.display = "block"; } span.onclick = function() { modal.style.display = "none"; } window.onclick = function(event) { if (event.target == modal) { modal.style.display = "none"; } }