Develop Reference

Image modals on multi-tab page

I want to create a multi-tabs page with an image modal on each tab.
I used code from w3school.com. The modal only shows on the first page but not in the others. No matter what image I click, the modal with that image will show only in the first page. I am new to web design, so I prefer to use CSS and simple JavaScript.
Can anybody help me figure out how to make the modal show on the correct page?
Edited on Oct 02, 2021, I revised my CSS and Javascript and fixed the issue using a loop. Just sharing for anyone might be interested in.
Revised JavaScript
///// Image display modals
// All page modals
var modals = document.querySelectorAll('.modal');
// Get the image and insert it inside the modal - use its "alt"
// text as a caption
var img = document.querySelectorAll("img.myImg")
var modalImg = document.querySelectorAll("img.modal-content")
var captionText = document.querySelectorAll(".modal-caption");
// Get the <span> element that closes the modal
var spans = document.getElementsByClassName("close");
// When the user clicks the image, open the modal
for (var i = 0; i < img.length; i++) {
img[i].onclick = function() {
for (var index in modals) {
modals[index].style.display = "block";
for (var index in modalImg) {
modalImg[index].src = this.src;};
for (var index in captionText) {
captionText[index].innerHTML = this.alt;}
}
}
}
// When the user clicks on <span> (x), close the modal
for (var i = 0; i < spans.length; i++) {
spans[i].onclick = function() {
for (var index in modals) {
if (typeof modals[index].style !== 'undefined') modals[index].style.display = "none";
}
}
}
// When the user clicks anywhere outside of the modal, close it
window.onclick = function(event) {
if (event.target.classList.contains('modal')) {
for (var index in modals) {
if (typeof modals[index].style !== 'undefined') modals[index].style.display = "none";
}
}
}
Revised CSS
* {box-sizing: border-box}
/* Set height of body and the document to 100% */
body, html {
height: 100%;
margin: 0;
font-family: Arial;
}
/* Style tab links */
.tablink {
background-color: #555;
color: white;
float: left;
border: none;
outline: none;
cursor: pointer;
padding: 14px 16px;
font-size: 17px;
width: 25%;
}
.tablink:hover {
background-color: #777;
}
/* Style the tab content (and add height:100% for full page content) */
.tabcontent {
color: white;
display: none;
padding: 100px 20px;
height: 100%;
}
#Home {background-color: red;}
#News {background-color: green;}
#Contact {background-color: blue;}
#About {background-color: orange;}
.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 */
.modal-caption {
margin: auto;
display: block;
width: 80%;
max-width: 700px;
text-align: center;
color: #ccc;
padding: 10px 0;
height: 150px;
}
/* Add Animation */
.modal-content, .modal-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%;
}
}
HTML
<button class="tablink" onclick="openPage('Home', this, 'red')">Home</button>
<button class="tablink" onclick="openPage('News', this, 'green')" id="defaultOpen">News</button>
<button class="tablink" onclick="openPage('Contact', this, 'blue')">Contact</button>
<button class="tablink" onclick="openPage('About', this, 'orange')">About</button>
<div id="Home" class="tabcontent">
<h2>Image Modal</h2>
<p>In this example, we use CSS to create a modal (dialog box) that is hidden by default.</p>
<p>We use JavaScript to trigger the modal and to display the current image inside the modal when it is clicked on. Also note that we use the value from the image's "alt" attribute as an image caption text inside the modal.</p>
<img id="myImg" src="img_nature.jpg" alt="Snow" style="width:100%;max-width:300px">
<!-- The Modal -->
<div id="myModal" class="modal">
<span class="close">×</span>
<img class="modal-content" id="img01">
<div id="caption"></div>
</div>
</div>
<div id="News" class="tabcontent">
<h2>Image Modal</h2>
<p>In this example, we use CSS to create a modal (dialog box) that is hidden by default.</p>
<p>We use JavaScript to trigger the modal and to display the current image inside the modal when it is clicked on. Also note that we use the value from the image's "alt" attribute as an image caption text inside the modal.</p>
<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">×</span>
<img class="modal-content" id="img01">
<div id="caption"></div>
</div>
</div>
<div id="Contact" class="tabcontent">
<h2>Image Modal</h2>
<p>In this example, we use CSS to create a modal (dialog box) that is hidden by default.</p>
<p>We use JavaScript to trigger the modal and to display the current image inside the modal when it is clicked on. Also note that we use the value from the image's "alt" attribute as an image caption text inside the modal.</p>
<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">×</span>
<img class="modal-content" id="img01">
<div id="caption"></div>
</div>
</div>
<div id="About" class="tabcontent">
<h3>About</h3>
<p>Who we are and what we do.</p>
</div>
Original CSS
* {box-sizing: border-box}
/* Set height of body and the document to 100% */
body, html {
height: 100%;
margin: 0;
font-family: Arial;
}
/* Style tab links */
.tablink {
background-color: #555;
color: white;
float: left;
border: none;
outline: none;
cursor: pointer;
padding: 14px 16px;
font-size: 17px;
width: 25%;
}
.tablink:hover {
background-color: #777;
}
/* Style the tab content (and add height:100% for full page content) */
.tabcontent {
color: white;
display: none;
padding: 100px 20px;
height: 100%;
}
#Home {background-color: red;}
#News {background-color: green;}
#Contact {background-color: blue;}
#About {background-color: orange;}
#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%;
}
}
Original JavaScript
<script>
function openPage(pageName,elmnt,color) {
var i, tabcontent, tablinks;
tabcontent = document.getElementsByClassName("tabcontent");
for (i = 0; i < tabcontent.length; i++) {
tabcontent[i].style.display = "none";
}
tablinks = document.getElementsByClassName("tablink");
for (i = 0; i < tablinks.length; i++) {
tablinks[i].style.backgroundColor = "";
}
document.getElementById(pageName).style.display = "block";
elmnt.style.backgroundColor = color;
}
// Get the element with id="defaultOpen" and click on it
document.getElementById("defaultOpen").click();
// 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";
}
</script>

Separate function for each modal will work out now , further you can look into this and loops for small code in the near future
function openPage(pageName, elmnt, color) {
var i, tabcontent, tablinks;
tabcontent = document.getElementsByClassName("tabcontent");
for (i = 0; i < tabcontent.length; i++) {
tabcontent[i].style.display = "none";
}
tablinks = document.getElementsByClassName("tablink");
for (i = 0; i < tablinks.length; i++) {
tablinks[i].style.backgroundColor = "";
}
document.getElementById(pageName).style.display = "block";
elmnt.style.backgroundColor = color;
}
// Get the element with id="defaultOpen" and click on it
document.getElementById("defaultOpen").click();
// 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";
}
// Get the 2nd modal
var modal2 = document.getElementById("myModal2");
// Get the image and insert it inside the modal - use its "alt" text as a caption
var img2 = document.getElementById("myImg2");
var modalImg2 = document.getElementById("img02");
var captionText2 = document.getElementById("caption2");
img2.onclick = function() {
modal2.style.display = "block";
modalImg2.src = this.src;
captionText2.innerHTML = this.alt;
}
// Get the 2nd <span> element that closes the modal
var span2 = document.getElementsByClassName("close")[1];
// When the user clicks on <span> (x), close the modal
span2.onclick = function() {
modal2.style.display = "none";
}
// Get the 3rd modal
var modal3 = document.getElementById("myModal3");
// Get the image and insert it inside the modal - use its "alt" text as a caption
var img3 = document.getElementById("myImg3");
var modalImg3 = document.getElementById("img03");
var captionText3 = document.getElementById("caption3");
img3.onclick = function() {
modal3.style.display = "block";
modalImg3.src = this.src;
captionText3.innerHTML = this.alt;
}
// Get the 2nd <span> element that closes the modal
var span3 = document.getElementsByClassName("close")[2];
// When the user clicks on <span> (x), close the modal
span3.onclick = function() {
modal3.style.display = "none";
}
* {
box-sizing: border-box
}
/* Set height of body and the document to 100% */
body,
html {
height: 100%;
margin: 0;
font-family: Arial;
}
/* Style tab links */
.tablink {
background-color: #555;
color: white;
float: left;
border: none;
outline: none;
cursor: pointer;
padding: 14px 16px;
font-size: 17px;
width: 25%;
}
.tablink:hover {
background-color: #777;
}
/* Style the tab content (and add height:100% for full page content) */
.tabcontent {
color: white;
display: none;
padding: 100px 20px;
height: 100%;
}
#Home {
background-color: red;
}
#News {
background-color: green;
}
#Contact {
background-color: blue;
}
#About {
background-color: orange;
}
.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%;
}
}
<button class="tablink" onclick="openPage('Home', this, 'red')">Home</button>
<button class="tablink" onclick="openPage('News', this, 'green')" id="defaultOpen">News</button>
<button class="tablink" onclick="openPage('Contact', this, 'blue')">Contact</button>
<button class="tablink" onclick="openPage('About', this, 'orange')">About</button>
<div id="Home" class="tabcontent">
<h2>Image Modal</h2>
<p>In this example, we use CSS to create a modal (dialog box) that is hidden by default.</p>
<p>We use JavaScript to trigger the modal and to display the current image inside the modal when it is clicked on. Also note that we use the value from the image's "alt" attribute as an image caption text inside the modal.</p>
<img id="myImg" src="img_nature.jpg" alt="Snow" style="width:100%;max-width:300px">
<!-- The Modal -->
<div id="myModal" class="modal">
<span class="close">×</span>
<img class="modal-content" id="img01">
<div id="caption" class="caption"></div>
</div>
</div>
<div id="News" class="tabcontent">
<h2>Image Modal</h2>
<p>In this example, we use CSS to create a modal (dialog box) that is hidden by default.</p>
<p>We use JavaScript to trigger the modal and to display the current image inside the modal when it is clicked on. Also note that we use the value from the image's "alt" attribute as an image caption text inside the modal.</p>
<img id="myImg2" class="myImg" src="img_snow.jpg" alt="Snow" style="width:100%;max-width:300px">
<!-- The Modal -->
<div id="myModal2" class="modal">
<span class="close">×</span>
<img class="modal-content" id="img02">
<div id="caption2" class="caption"></div>
</div>
</div>
<div id="Contact" class="tabcontent">
<h2>Image Modal</h2>
<p>In this example, we use CSS to create a modal (dialog box) that is hidden by default.</p>
<p>We use JavaScript to trigger the modal and to display the current image inside the modal when it is clicked on. Also note that we use the value from the image's "alt" attribute as an image caption text inside the modal.</p>
<img id="myImg3" class="myImg" src="img_snow.jpg" alt="Snow" style="width:100%;max-width:300px">
<!-- The Modal -->
<div id="myModal3" class="modal">
<span class="close">×</span>
<img class="modal-content" id="img03">
<div id="caption3" class="caption"></div>
</div>
</div>
<div id="About" class="tabcontent">
<h3>About</h3>
<p>Who we are and what we do.</p>
</div>

how can display a qr in a window modal?

I have this function that returns a value to display a qr
def some():
return http.request.render('as_website_sale_onepage.cria', {
'QRimage':orders.qrImage,
})
it displays in that section
<div>
<img if="QRimage" t-att-src="'data:image/jpg;base64,'+ QRimage" alt="QrCode" />
</div>
the result is this
QR image
how can i display that in a modal window?

You can use the modal from W3School W3School: How To Make a Modal Box With CSS and JavaScript
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 on 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";
}
}
/* The Modal (background) */
.modal {
display: none; /* Hidden by default */
position: fixed; /* Stay in place */
z-index: 1; /* Sit on top */
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/Box */
.modal-content {
background-color: #fefefe;
margin: 15% auto; /* 15% from the top and centered */
padding: 20px;
border: 1px solid #888;
width: 80%; /* Could be more or less, depending on screen size */
}
/* The Close Button */
.close {
color: #aaa;
float: right;
font-size: 28px;
font-weight: bold;
}
.close:hover,
.close:focus {
color: black;
text-decoration: none;
cursor: pointer;
}
<!-- Trigger/Open The Modal -->
<button id="myBtn">Open Modal</button>
<!-- The Modal -->
<div id="myModal" class="modal">
<!-- Modal content -->
<div class="modal-content">
<span class="close">×</span>
<img src="https://i.stack.imgur.com/8ovP4.png" alt="Qr Code" />
</div>
</div>

Creating two modal buttons that open different popup windows

Essentially I have two links. I would like link 1 to open up a popup (let's say Popup 1), and link 2 to open up a separate popup (Popup 2). As it is now, both open only Popup 2. What exactly in this code needs to be changed?
The code is visible here:
https://jsfiddle.net/mattwalker1092/xxgt4tm5/
Or, alternatively, below:
body {
background: #1f1f2e; }
ppopup {
color: #000000;
font-family: "cambria";
font-size: 22px }
.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: scroll; /* 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 {
background-color: #dbd9d7;
text-align: center;
margin: auto;
padding: 20px;
border: 1px solid #888;
width: 50%;
height: 70%;
overflow-x: hidden;
overflow-y: scroll; }
.close {
color: #aaaaaa;
float: right;
font-size: 28px;
font-weight: bold; }
.close:hover,
.close:focus {
color: #000;
text-decoration: none;
cursor: pointer; }
button {
background:none!important;
border:none;
padding:0!important;
color: #cc9966;
font-family: "Century Gothic";
font-size: 16px;
text-decoration: none;}
.txt:hover {
text-decoration: underline; }
<!-- Trigger/Open The Modal -->
<center><button id="myBtnONE"><span class="txt" style="cursor:pointer">Link 1</span></button></center>
<!-- The Modal -->
<div id="myModalONE" class="modal">
<!-- Modal content -->
<div class="modal-content">
<span class="close">×</span>
<p><ppopup>
This is my FIRST TEST
</ppopup></p>
</div>
</div>
<script>
// Get the modal
var modal = document.getElementById('myModalONE');
// Get the button that opens the modal
var btn = document.getElementById("myBtnONE");
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"; } }
</script>
<center><button id="myBtnTWO"><span class="txt" style="cursor:pointer">Link 2</span></button></center>
<!-- The Modal -->
<div id="myModalTWO" class="modal">
<!-- Modal content -->
<div class="modal-content">
<span class="close">×</span>
<p><ppopup>
This is a SECOND TEST
</ppopup></p>
</div>
</div>
<script>
// Get the modal
var modal = document.getElementById('myModalTWO');
// Get the button that opens the modal
var btn = document.getElementById("myBtnTWO");
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"; } }
</script>

See https://jsfiddle.net/nf6bcpdu/. Just use some onclick events to bind what you want to happen.
<center><button id="myBtnONE"><span class="txt" style="cursor:pointer" onclick="OpenModalOne();">Link 1</span></button></center>
<!-- The Modal -->
<div id="myModalONE" class="modal">
<!-- Modal content -->
<div class="modal-content">
<span class="close" onclick="CloseModalOne();">×</span>
<p><ppopup>
This is my FIRST TEST
</ppopup></p>
</div>
</div>
<script>
function OpenModalOne() {
var modal = document.getElementById('myModalONE');
modal.style.display = "block";
}
function OpenModalTwo() {
var modal = document.getElementById('myModalTWO');
modal.style.display = "block";
}
function CloseModalOne() {
var modal = document.getElementById('myModalONE');
modal.style.display = "none";
}
function CloseModalTwo() {
var modal = document.getElementById('myModalTWO');
modal.style.display = "none";
}
</script>script>
<center><button id="myBtnTWO"><span class="txt" style="cursor:pointer" onclick="OpenModalTwo();">Link 2</span></button></center>
<!-- The Modal -->
<div id="myModalTWO" class="modal">
<!-- Modal content -->
<div class="modal-content">
<span class="close" onclick="CloseModalTwo();">×</span>
<p><ppopup>
This is a SECOND TEST
</ppopup></p>
</div>
</div>

Modal close button not working

This is the code. If I open the modal, the close button will not work and will not close until the page is refreshed.
// 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";
}
}
/* Create three columns of equal width */
.columns {
float: left;
width: 33.3%;
padding: 8px;
}
/* Style the list */
.price {
list-style-type: none;
border: 1px solid #eee;
margin: 0;
padding: 0;
-webkit-transition: 0.3s;
transition: 0.3s;
}
/* Add shadows on hover */
.price:hover {
box-shadow: 0 8px 12px 0 rgba(0, 0, 0, 0.2)
}
/* Pricing header */
.price .header {
background-color: #111;
color: white;
font-size: 25px;
}
/* List items */
.price li {
border-bottom: 1px solid #eee;
padding: 20px;
text-align: center;
}
/* Grey list item */
.price .grey {
background-color: #eee;
font-size: 20px;
}
/* The "Sign Up" button */
.button {
background-color: #4CAF50;
border: none;
color: white;
padding: 10px 25px;
text-align: center;
text-decoration: none;
font-size: 18px;
}
/* Change the width of the three columns to 100%
(to stack horizontally on small screens) */
#media only screen and (max-width: 600px) {
.columns {
width: 100%;
}
}
/* The Modal (background) */
.modal {
display: none;
/* Hidden by default */
position: fixed;
/* Stay in place */
z-index: 1;
/* Sit on top */
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/Box */
.modal-content {
background-color: #fefefe;
margin: 15% auto;
/* 15% from the top and centered */
padding: 20px;
border: 1px solid #888;
width: 80%;
/* Could be more or less, depending on screen size */
}
/* The Close Button */
.close {
color: #aaa;
float: right;
font-size: 28px;
font-weight: bold;
}
.close:hover,
.close:focus {
color: black;
text-decoration: none;
cursor: pointer;
}
<div class="columns">
<ul class="price">
<li class="header">Hard Drive Format</li>
<li class="grey">£10</li>
<li>Format Hard Drive</li>
<li>Removes ALL Files From Drive</li>
<li>Fresh Install Windows</li>
<li class="grey"><button onclick="document.getElementById('myModal').style.display='block'">Sign
Up</button></li>
</ul>
</div>
<!-- The Modal -->
<div id="myModal" class="modal">
<!-- Modal content -->
<div class="modal-content">
<span class="close">×</span>
<p>Some text in the Modal..</p>
</div>
</div>
All I want is for the modal to close when the button is clicked.

In your code there is no element with id myBtn
so remove the following code
// Get the button that opens the modal
var btn = document.getElementById("myBtn");
// When the user clicks the button, open the modal
btn.onclick = function() {
modal.style.display = "block";
}
and it will work fine

You didn't gave the button an ID. So the javascript was failing on that line where you were adding an event listener to the button. So the statement that follows were not executed.
<div class="columns">
<ul class="price">
<li class="header">Hard Drive Format</li>
<li class="grey">£10</li>
<li>Format Hard Drive</li>
<li>Removes ALL Files From Drive</li>
<li>Fresh Install Windows</li>
<li class="grey"><button id="myBtn">Sign Up</button></li>
</ul>
</div>
<!-- The Modal -->
<div id="myModal" style="display:none;" class="modal">
<!-- Modal content -->
<div class="modal-content">
<span class="close">×</span>
<p>Some text in the Modal..</p>
</div>
</div>
// 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";
}
}
Here is the solution : https://jsfiddle.net/xf7whk0o/

Use this in your closing button.
data-dismiss="modal"
Use it like:
<button type="btn btn-default" data-dismiss="modal">CLOSE</button>

HTML & CSS & JS error

<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>
<script src='script.js'></script>
<!-- Trigger/Open The Modal -->
<button id="myBtn">Open Modal</button>
<!-- The Modal -->
<div id="myModal" class="modal">
<!-- Modal content -->
<div class="modal-content">
<span class="close">×</span>
<p>Some text in the Modal..</p>
</div>
</div>
</body>
</html>
CSS:
/* 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(0,0,0,0.4); /* Black w/ opacity */
}
/* Modal Content */
.modal-content {
background-color: #fefefe;
margin: auto;
padding: 20px;
border: 1px solid #888;
width: 80%;
}
/* The Close Button */
.close {
color: #aaaaaa;
float: right;
font-size: 28px;
font-weight: bold;
}
.close:hover,
.close:focus {
color: #000;
text-decoration: none;
cursor: pointer;
}
JS:
// 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";
}
}
I have all this code, and it's all linked up as you can see in the code. But for some reason, it doesn't work unless I use style and script tags within the HTML. Why is this and how would I fix it?
This is all in a folder on my computer. I plan to upload it to the web later.

Try adding <script src='script.js'></script> before your </body> tag.
It seems that you are executing your JS script that depends on DOM elements script before their are loaded

if you have a folder which contain this file 3- index.html , style.css, and script.js
So basically you need to shift your script.js before body tag
CHECK THE HTML STRUCTURE BELOW ADDITIONALLY You can add the latest compiled jQuery
//your script.js structure-
// 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";
}
}
/*IN YOUR STYLE.CSS */
/* 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(0,0,0,0.4); /* Black w/ opacity */
}
/* Modal Content */
.modal-content {
background-color: #fefefe;
margin: auto;
padding: 20px;
border: 1px solid #888;
width: 80%;
}
/* The Close Button */
.close {
color: #aaaaaa;
float: right;
font-size: 28px;
font-weight: bold;
}
.close:hover,
.close:focus {
color: #000;
text-decoration: none;
cursor: pointer;
}
<!--in your index.html structure like-->
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css" href="style.css" />
</head>
<body>
<!-- Trigger/Open The Modal -->
<button id="myBtn">Open Modal</button>
<!-- The Modal -->
<div id="myModal" class="modal">
<!-- Modal content -->
<div class="modal-content">
<span class="close">×</span>
<p>Some text in the Modal..</p>
</div>
</div>
<script src="https://code.jquery.com/jquery-3.1.0.min.js"></script><!-- ADDITIONALLY YOU CAN ADD THIS.. But RIGHT NOW Modal WILL RUN WITHOUT THIS-->
<script src='script.js'></script>
</body>
</html>