Slider & Light Box - Javascript conflict - javascript

Would you anyone please help resolve this conflict? I would really appreciate that.
I am trying to use two javascripts of Slider and Light Box from w3schools.com on one HTML page but, I guess, both javascripts use the same names(or values) for each function so when I use them in one page at the same time, they don't work. but when I remove one set of css/html/javascript for each slider or light box, either works well.
Please help this for me.
Thank you very much in advance.
CSS
<style>
body {
font-family: Verdana, sans-serif;
margin: 0;
}
/* --------- Slider ---------- */
* {box-sizing:border-box}
/* Slideshow container */
.slideshow-container {
max-width: 1000px;
position: relative;
margin: auto;
}
.mySlides {
display: none;
}
/* Next & previous buttons */
.prev, .next {
cursor: pointer;
position: absolute;
top: 50%;
width: auto;
margin-top: -22px;
padding: 16px;
color: white;
font-weight: bold;
font-size: 18px;
transition: 0.6s ease;
border-radius: 0 3px 3px 0;
}
/* Position the "next button" to the right */
.next {
right: 0;
border-radius: 3px 0 0 3px;
}
/* On hover, add a black background color with a little bit see-through */
.prev:hover, .next:hover {
background-color: rgba(0,0,0,0.8);
}
/* Caption text */
.text {
color: #f2f2f2;
font-size: 15px;
padding: 8px 12px;
position: absolute;
bottom: 8px;
width: 100%;
text-align: center;
}
/* Number text (1/3 etc) */
.numbertext {
color: #f2f2f2;
font-size: 12px;
padding: 8px 12px;
position: absolute;
top: 0;
}
/* The dots/bullets/indicators */
.dot {
cursor:pointer;
height: 13px;
width: 13px;
margin: 0 2px;
background-color: #bbb;
border-radius: 50%;
display: inline-block;
transition: background-color 0.6s ease;
}
.active, .dot:hover {
background-color: #717171;
}
/* Fading animation */
.fade {
-webkit-animation-name: fade;
-webkit-animation-duration: 1.5s;
animation-name: fade;
animation-duration: 1.5s;
}
#-webkit-keyframes fade {
from {opacity: .4}
to {opacity: 1}
}
#keyframes fade {
from {opacity: .4}
to {opacity: 1}
}
/* ----- Light Box -------*/
.row > .column {
padding: 0 8px;
}
.row:after {
content: "";
display: table;
clear: both;
}
.column {
float: left;
width: 25%;
}
/* The Modal (background) */
.modal {
display: none;
position: fixed;
z-index: 1;
padding-top: 100px;
left: 0;
top: 0;
width: 100%;
height: 100%;
overflow: auto;
background-color: black;
}
/* Modal Content */
.modal-content {
position: relative;
background-color: transparent;
margin: auto;
padding: 0;
width: 90%;
max-width: 1200px;
border: none;
}
/* The Close Button */
.close {
color: white;
position: absolute;
top: 10px;
right: 25px;
font-size: 35px;
font-weight: bold;
}
.close:hover,
.close:focus {
color: #999;
text-decoration: none;
cursor: pointer;
}
.mySlides {
display: none;
}
.cursor {
cursor: pointer
}
/* Next & previous buttons */
.prev,
.next {
cursor: pointer;
position: absolute;
top: 50%;
width: auto;
padding: 16px;
margin-top: -50px;
color: white;
font-weight: bold;
font-size: 20px;
transition: 0.6s ease;
border-radius: 0 3px 3px 0;
user-select: none;
-webkit-user-select: none;
}
/* Position the "next button" to the right */
.next {
right: 0;
border-radius: 3px 0 0 3px;
}
/* On hover, add a black background color with a little bit see-through */
.prev:hover,
.next:hover {
background-color: rgba(0, 0, 0, 0.8);
}
/* Number text (1/3 etc) */
.numbertext {
color: #f2f2f2;
font-size: 12px;
padding: 8px 12px;
position: absolute;
top: 0;
}
img {
margin-bottom: -4px;
}
.caption-container {
text-align: center;
background-color: black;
padding: 2px 16px;
color: white;
}
.demo {
opacity: 0.6;
}
.active,
.demo:hover {
opacity: 1;
}
img.hover-shadow {
transition: 0.3s
}
.hover-shadow:hover {
box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19)
}
.container {margin: 0 auto; max-width: 1000px;}
</style>
HTML
<body>
<div class="container">
<!-- ================ Slideshow ================ -->
<div class="slideshow-container mt20 mb10">
<div class="mySlides fade">
<div class="numbertext">1 / 3</div>
<img src="https://www.w3schools.com/howto/img_nature_wide.jpg" style="width:100%">
<div class="text">Caption Text</div>
</div>
<div class="mySlides fade">
<div class="numbertext">2 / 3</div>
<img src="https://www.w3schools.com/howto/img_fjords_wide.jpg" style="width:100%">
<div class="text">Caption Two</div>
</div>
<div class="mySlides fade">
<div class="numbertext">3 / 3</div>
<img src="https://www.w3schools.com/howto/img_mountains_wide.jpg" style="width:100%">
<div class="text">Caption Three</div>
</div>
<a class="prev" onclick="plusSlides(-1)">❮</a>
<a class="next" onclick="plusSlides(1)">❯</a>
</div>
<div style="text-align:center;margin-top:10px;">
<span class="dot" onclick="currentSlide(1)"></span>
<span class="dot" onclick="currentSlide(2)"></span>
<span class="dot" onclick="currentSlide(3)"></span>
</div> <!-- // Slider -->
<!-- Lightbox -->
<h2 style="text-align:center">Lightbox</h2>
<div class="row">
<div class="column">
<img src="https://www.w3schools.com/howto/img_nature.jpg" style="width:100%" onclick="openModal();currentSlide(1)" class="hover-shadow cursor">
</div>
<div class="column">
<img src="https://www.w3schools.com/howto/img_fjords.jpg" style="width:100%" onclick="openModal();currentSlide(2)" class="hover-shadow cursor">
</div>
<div class="column">
<img src="https://www.w3schools.com/howto/img_mountains.jpg" style="width:100%" onclick="openModal();currentSlide(3)" class="hover-shadow cursor">
</div>
<div class="column">
<img src="https://www.w3schools.com/howto/img_lights.jpg" style="width:100%" onclick="openModal();currentSlide(4)" class="hover-shadow cursor">
</div>
</div>
<div id="myLightBox" class="modal">
<span class="close cursor" onclick="closeModal()">×</span>
<div class="modal-content">
<div class="LB-Slides">
<div class="numbertext">1 / 4</div>
<img src="https://www.w3schools.com/howto/img_nature_wide.jpg" style="width:100%">
</div>
<div class="LB-Slides">
<div class="numbertext">2 / 4</div>
<img src="https://www.w3schools.com/howto/img_fjords_wide.jpg" style="width:100%">
</div>
<div class="LB-Slides">
<div class="numbertext">3 / 4</div>
<img src="https://www.w3schools.com/howto/img_mountains_wide.jpg" style="width:100%">
</div>
<div class="LB-Slides">
<div class="numbertext">4 / 4</div>
<img src="https://www.w3schools.com/howto/img_lights_wide.jpg" style="width:100%">
</div>
<a class="prev" onclick="plusSlides(-1)">❮</a>
<a class="next" onclick="plusSlides(1)">❯</a>
<div class="caption-container">
<p id="caption"></p>
</div>
<div class="column">
<img class="demo cursor" src="https://www.w3schools.com/howto/img_nature_wide.jpg" style="width:100%" onclick="currentSlide(1)" alt="Nature and sunrise">
</div>
<div class="column">
<img class="demo cursor" src="https://www.w3schools.com/howto/img_fjords_wide.jpg" style="width:100%" onclick="currentSlide(2)" alt="Trolltunga, Norway">
</div>
<div class="column">
<img class="demo cursor" src="https://www.w3schools.com/howto/img_mountains_wide.jpg" style="width:100%" onclick="currentSlide(3)" alt="Mountains and fjords">
</div>
<div class="column">
<img class="demo cursor" src="https://www.w3schools.com/howto/img_lights_wide.jpg" style="width:100%" onclick="currentSlide(4)" alt="Northern Lights">
</div>
</div>
</div>
</div><!-- // Lightbox -->
</div>
Javascript
<script>
/* --------- Slider ---------- */
var slideIndex = 1;
showSlides(slideIndex);
setInterval(function(){ showSlides(++slideIndex); }, 4000);
function plusSlides(n) {
showSlides(slideIndex += n);
}
function currentSlide(n) {
showSlides(slideIndex = n);
}
function showSlides(n) {
var i;
var slides = document.getElementsByClassName("mySlides");
var dots = document.getElementsByClassName("dot");
if (n > slides.length) {slideIndex = 1}
if (n < 1) {slideIndex = slides.length}
for (i = 0; i < slides.length; i++) {
slides[i].style.display = "none";
}
for (i = 0; i < dots.length; i++) {
dots[i].className = dots[i].className.replace(" active", "");
}
slides[slideIndex-1].style.display = "block";
dots[slideIndex-1].className += " active";
}
/* --------- LightBox ---------- */
function openModal() {
document.getElementById('myLightBox').style.display = "block";
}
function closeModal() {
document.getElementById('myLightBox').style.display = "none";
}
var slideIndex = 1;
showSlides(slideIndex);
function plusSlides(n) {
showSlides(slideIndex += n);
}
function currentSlide(n) {
showSlides(slideIndex = n);
}
function showSlides(n) {
var i;
var slides = document.getElementsByClassName("LB-Slides");
var dots = document.getElementsByClassName("demo");
var captionText = document.getElementById("caption");
if (n > slides.length) {slideIndex = 1}
if (n < 1) {slideIndex = slides.length}
for (i = 0; i < slides.length; i++) {
slides[i].style.display = "none";
}
for (i = 0; i < dots.length; i++) {
dots[i].className = dots[i].className.replace(" active", "");
}
slides[slideIndex-1].style.display = "block";
dots[slideIndex-1].className += " active";
captionText.innerHTML = dots[slideIndex-1].alt;
}
/* --------- //LightBox ---------- */
</script>
</body>

First of all – yes, you are right, both of your scripts are conflicting to each other due the same methods names. Since it's written in global scope (window) you basically override each other functionality.
You could try to use JavaScript module pattern to isolate scope of each of your "widgets", even if you gonna use the same methods names, your code will be executed in it's own scope.
As quick example how to rewrite this into modules:
http://jsbin.com/pipajawiwa/1/edit?html,js,output
/* --------- Slider ---------- */
var slider = (function() {
var slider = {};
slider.setIntervals = function() {
setInterval(function() {
slider.showSlides(++slider.slideIndex);
}, 4000);
};
slider.plusSlides = function(n) {
slider.showSlides(slider.slideIndex += n);
};
slider.currentSlide = function(n) {
slider.showSlides(slider.slideIndex = n);
};
slider.showSlides = function(n) {
var i;
var slides = document.getElementsByClassName("mySlides");
var dots = document.getElementsByClassName("dot");
if (n > slides.length) {
slider.slideIndex = 1
}
if (n < 1) {
slider.slideIndex = slides.length
}
for (i = 0; i < slides.length; i++) {
slides[i].style.display = "none";
}
for (i = 0; i < dots.length; i++) {
dots[i].className = dots[i].className.replace(" active", "");
}
slides[slider.slideIndex - 1].style.display = "block";
dots[slider.slideIndex - 1].className += " active";
};
slider.init = function() {
slider.slideIndex = 1;
slider.showSlides(slider.slideIndex);
slider.setIntervals();
};
return slider;
})();
/* --------- LightBox ---------- */
var lightbox = (function() {
var lightbox = {};
lightbox.openModal = function() {
document.getElementById('myLightBox').style.display = "block";
};
lightbox.closeModal = function() {
document.getElementById('myLightBox').style.display = "none";
};
lightbox.plusSlides = function(n) {
lightbox.showSlides(lightbox.slideIndex += n);
};
lightbox.currentSlide = function(n) {
lightbox.showSlides(lightbox.slideIndex = n);
};
lightbox.showSlides = function(n) {
var i;
var slides = document.getElementsByClassName("LB-Slides");
var dots = document.getElementsByClassName("demo");
var captionText = document.getElementById("caption");
if (n > slides.length) {
lightbox.slideIndex = 1
}
if (n < 1) {
lightbox.slideIndex = slides.length
}
for (i = 0; i < slides.length; i++) {
slides[i].style.display = "none";
}
for (i = 0; i < dots.length; i++) {
dots[i].className = dots[i].className.replace(" active", "");
}
slides[lightbox.slideIndex - 1].style.display = "block";
dots[lightbox.slideIndex - 1].className += " active";
captionText.innerHTML = dots[lightbox.slideIndex - 1].alt;
};
lightbox.init = function() {
lightbox.slideIndex = 1;
lightbox.showSlides(lightbox.slideIndex);
};
return lightbox;
})();
slider.init(); // initialize slider module (widget);
lightbox.init(); // initialize lightbox module (widget);
Please make note that you also need to adjust your html onclick events, since it's should be called each widget methods, not global once.
P.S.: I'm not big fan of both of this code snippets from w3school (in terms of code quality, performance aspects, learning patterns), but it's completely another topic to discuss. But in order "to make it work" this link to jsbin above should help.

Related

How would I approach adding automation to a slideshow?

I built a JS slideshow with clickable indicators. I would like for my slideshow to play automatically, while maintaining the functionality of the indicator buttons.
In the code example below, I attempted to add a setTimeout() method to change the image every 2000ms, but it seems to not be working. What would be the best approach to change the JS so I have some automation? I also attempted to use the setInterval method with no luck. I will provide the code below:
Thank you in advance for the help/tips/and advice
var editorialSlideIndex = 1;
showEditorialSlides(editorialSlideIndex);
//Next/previous controls
function plusSlides(n) {
showEditorialSlides(editorialSlideIndex += n);
}
//Thumbnail image controls
function currentSlide(n) {
showEditorialSlides(editorialSlideIndex = n);
}
function showEditorialSlides(n) {
var i;
var slides = document.getElementsByClassName("editorial-slideshow");
var slideDotInd = document.getElementsByClassName("slideDotInd");
if (n > slides.length) {
editorialSlideIndex = 1
}
if (n < 1) {
editorialSlideIndex = slides.length
}
for (i = 0; i < slides.length; i++) {
slides[i].style.display = "none";
}
for (i = 0; i < slideDotInd.length; i++) {
slideDotInd[i].className = slideDotInd[i].className.replace(" active-slider", "");
}
slides[editorialSlideIndex - 1].style.display = "block";
slideDotInd[editorialSlideIndex - 1].className += " active-slider";
setTimeout(showEditorialSlides, 2000); // Change image every 2 seconds
}
/*Slideshow Container */
.editorial-slideshow-container {
padding-top: 15px;
position: relative;
margin: auto;
}
/*Default Hide Images*/
.editorial-slideshow {
display: none;
}
/*Next and previous buttons*/
.prev,
.next {
cursor: pointer;
position: absolute;
top: 50%;
width: auto;
margin-top: -34px;
padding: 10px;
color: white;
font-weight: bold;
font-size: 34px;
transition: 0.6s ease;
border-radius: 0 3px 3px 0;
user-select: none;
background-color: rgba(0, 128, 115, .5);
}
/* Position "next button" */
.next {
right: 0;
border-radius: 3px 0 0 3px;
}
/* On hover, background color */
.prev:hover,
.next:hover {
background-color: rgba(0, 128, 115, .8);
}
/* Caption text
.text {
color: #f2f2f2;
font-size: 15px;
padding: 8px 12px;
position: absolute;
bottom: 8px;
width: 100%;
text-align: center;
}
Number text (1/3 etc)
.numbertext {
color: #f2f2f2;
font-size: 12px;
padding: 8px 12px;
position: absolute;
top: 15;
}
*/
/* The slideslideDotInd/bullets/indicators */
.slideDotInd {
cursor: pointer;
height: 15px;
width: 15px;
margin: 15px 2px;
background-color: #bbb;
border-radius: 50%;
display: inline-block;
transition: background-color 0.6s ease;
}
.active-slider,
.slideDotInd:hover {
background-color: #717171;
}
/* Fading animation */
.fade {
-webkit-animation-name: fade;
-webkit-animation-duration: 1.5s;
animation-name: fade;
animation-duration: .25s;
}
#-webkit-keyframes fade {
from {
opacity: .8
}
to {
opacity: 1
}
}
#keyframes fade {
from {
opacity: .8
}
to {
opacity: 1
}
}
#media only screen and (max-width: 425px) {
#CGConainer .banner-title H1 {
line-height: 50px;
}
}
#media only screen and (min-width: 768px) {
.editorial-slideshow-container {
width: 75%;
/*Max width is 576px*/
}
}
#media only screen and (min-width: 1024px) {
.editorial-slideshow-container {
width: 50%;
}
}
<div class="editorial-slideshow-container">
<div class="editorial-slideshow fade">
<img src="https://storage.googleapis.com/img.triggermail.io/hammacher/slider-1.jpg" style="width:100%">
</div>
<div class="editorial-slideshow fade">
<img src="https://storage.googleapis.com/img.triggermail.io/hammacher/slider-2.jpg" style="width:100%">
</div>
<div class="editorial-slideshow fade">
<img src="https://storage.googleapis.com/img.triggermail.io/hammacher/slider-3.jpg" style="width:100%">
</div>
<div class="editorial-slideshow fade">
<img src="https://storage.googleapis.com/img.triggermail.io/hammacher/slider-4a.jpg" style="width:100%">
</div>
<div class="editorial-slideshow fade">
<img src="https://storage.googleapis.com/img.triggermail.io/hammacher/slider-5a.jpg" style="width:100%">
</div>
<div class="editorial-slideshow fade">
<img src="https://storage.googleapis.com/img.triggermail.io/hammacher/slider-6.jpg" style="width:100%">
</div>
<div class="editorial-slideshow fade">
<img src="https://storage.googleapis.com/img.triggermail.io/hammacher/slider-7.jpg" style="width:100%">
</div>
<div class="editorial-slideshow fade">
<img src="https://storage.googleapis.com/img.triggermail.io/hammacher/slider-8.jpg" style="width:100%">
</div>
<div class="editorial-slideshow fade">
<img src="https://storage.googleapis.com/img.triggermail.io/hammacher/slider-9.jpg" style="width:100%">
</div>
<div class="editorial-slideshow fade">
<img src="https://storage.googleapis.com/img.triggermail.io/hammacher/slider-10.jpg" style="width:100%">
</div>
<p class="prev" onclick="plusSlides(-1)">‹</p>
<p class="next" onclick="plusSlides(1)">›</p>
</div>
<div style="text-align:center">
<span class="slideDotInd" onclick="currentSlide(1)"></span>
<span class="slideDotInd" onclick="currentSlide(2)"></span>
<span class="slideDotInd" onclick="currentSlide(3)"></span>
<span class="slideDotInd" onclick="currentSlide(4)"></span>
<span class="slideDotInd" onclick="currentSlide(5)"></span>
<span class="slideDotInd" onclick="currentSlide(6)"></span>
<span class="slideDotInd" onclick="currentSlide(7)"></span>
<span class="slideDotInd" onclick="currentSlide(8)"></span>
<span class="slideDotInd" onclick="currentSlide(9)"></span>
<span class="slideDotInd" onclick="currentSlide(10)"></span>
</div>
It's such a small change.
The way you called setTimeout is wrong.
function showEditorialSlides(n) {
var i;
var slides = document.getElementsByClassName("editorial-slideshow");
var slideDotInd = document.getElementsByClassName("slideDotInd");
if (n > slides.length) {
editorialSlideIndex = 1
}
if (n < 1) {
editorialSlideIndex = slides.length
}
for (i = 0; i < slides.length; i++) {
slides[i].style.display = "none";
}
for (i = 0; i < slideDotInd.length; i++) {
slideDotInd[i].className = slideDotInd[i].className.replace(" active-slider", "");
}
slides[editorialSlideIndex - 1].style.display = "block";
slideDotInd[editorialSlideIndex - 1].className += " active-slider";
setTimeout(() => showEditorialSlides(editorialSlideIndex = (n+1)), 2000); // Change image every 2 seconds
}
And that was the reason your function was being called incorrectly.
EDIT: I forgot to mention the reason. There was no way JavaScript knew what parameters you were passing to the function when you're trying to recurse.
You can try it out in the fiddle

Slideshow / Carousel Javascript not working in an external file

I am new to programming in general, so I apologize if my question is not constructive and clear but I took my time and hope to visualize the issue. I tested out Javascript and want an imageslider with basic javascript.
However I cannot figure out why my code will not funcntion when the javascript is written in an external sheet.
The imageslider will not initially show up when the page load, but it is working when written inside HTML file.
Here is the code from w3schools example
here is the fiddle
The javascript:
var slideIndex = 1;
showSlides(slideIndex);
// Next/previous controls
function plusSlides(n) {
showSlides(slideIndex += n);
}
// Thumbnail image controls
function currentSlide(n) {
showSlides(slideIndex = n);
}
function showSlides(n) {
var i;
var slides = document.getElementsByClassName("mySlides");
var dots = document.getElementsByClassName("dot");
if (n > slides.length) {slideIndex = 1}
if (n < 1) {slideIndex = slides.length}
for (i = 0; i < slides.length; i++) {
slides[i].style.display = "none";
}
for (i = 0; i < dots.length; i++) {
dots[i].className = dots[i].className.replace(" active", "");
}
slides[slideIndex-1].style.display = "block";
dots[slideIndex-1].className += " active";
}
Everything seems to be working perfectly fine untill I put this into separate script file.
<script src="js/slider.js"></script>
Function is working here with javascript inside html
Function is NOT working here with javascript written in external file.
`
this is what debug info says
Uncaught TypeError: Cannot read property 'style' of undefined
at showSlides (slider.js:27)
at slider.js:3`
showSlides(slideIndex); This shows error
slides[slideIndex-1].style.display = "block"; This shows error
Please check where you have placed you <script> tag if it is placed in <head> ,then place it just above the </body> this will solve your problem.
Please reffer this code:
script.js
var slideIndex = 1;
showSlides(slideIndex);
function plusSlides(n) {
showSlides(slideIndex += n);
}
function currentSlide(n) {
showSlides(slideIndex = n);
}
function showSlides(n) {
var i;
var slides = document.getElementsByClassName("mySlides");
var dots = document.getElementsByClassName("dot");
if (n > slides.length) {
slideIndex = 1
}
if (n < 1) {
slideIndex = slides.length
}
for (i = 0; i < slides.length; i++) {
slides[i].style.display = "none";
}
for (i = 0; i < dots.length; i++) {
dots[i].className = dots[i].className.replace(" active", "");
}
slides[slideIndex - 1].style.display = "block";
dots[slideIndex - 1].className += " active";
}
index.html
<!DOCTYPE html>
<html>
<head>
<title>Sample</title>
<style>
* {
box-sizing: border-box
}
body {
font-family: Verdana, sans-serif;
margin: 0
}
.mySlides {
display: none
}
img {
vertical-align: middle;
}
/* Slideshow container */
.slideshow-container {
max-width: 1000px;
position: relative;
margin: auto;
}
/* Next & previous buttons */
.prev,
.next {
cursor: pointer;
position: absolute;
top: 50%;
width: auto;
padding: 16px;
margin-top: -22px;
color: white;
font-weight: bold;
font-size: 18px;
transition: 0.6s ease;
border-radius: 0 3px 3px 0;
user-select: none;
}
/* Position the "next button" to the right */
.next {
right: 0;
border-radius: 3px 0 0 3px;
}
/* On hover, add a black background color with a little bit see-through */
.prev:hover,
.next:hover {
background-color: rgba(0, 0, 0, 0.8);
}
/* Caption text */
.text {
color: #f2f2f2;
font-size: 15px;
padding: 8px 12px;
position: absolute;
bottom: 8px;
width: 100%;
text-align: center;
}
/* Number text (1/3 etc) */
.numbertext {
color: #f2f2f2;
font-size: 12px;
padding: 8px 12px;
position: absolute;
top: 0;
}
/* The dots/bullets/indicators */
.dot {
cursor: pointer;
height: 15px;
width: 15px;
margin: 0 2px;
background-color: #bbb;
border-radius: 50%;
display: inline-block;
transition: background-color 0.6s ease;
}
.active,
.dot:hover {
background-color: #717171;
}
/* Fading animation */
.fade {
-webkit-animation-name: fade;
-webkit-animation-duration: 1.5s;
animation-name: fade;
animation-duration: 1.5s;
}
#-webkit-keyframes fade {
from {
opacity: .4
}
to {
opacity: 1
}
}
#keyframes fade {
from {
opacity: .4
}
to {
opacity: 1
}
}
/* On smaller screens, decrease text size */
#media only screen and (max-width: 300px) {
.prev,
.next,
.text {
font-size: 11px
}
}
</style>
</head>
<body>
<div class="slideshow-container">
<div class="mySlides fade">
<div class="numbertext">1 / 3</div>
<img src="img_nature_wide.jpg" style="width:100%">
<div class="text">Caption Text</div>
</div>
<div class="mySlides fade">
<div class="numbertext">2 / 3</div>
<img src="img_snow_wide.jpg" style="width:100%">
<div class="text">Caption Two</div>
</div>
<div class="mySlides fade">
<div class="numbertext">3 / 3</div>
<img src="img_mountains_wide.jpg" style="width:100%">
<div class="text">Caption Three</div>
</div>
<a class="prev" onclick="plusSlides(-1)">❮</a>
<a class="next" onclick="plusSlides(1)">❯</a>
</div>
<br>
<div style="text-align:center">
<span class="dot" onclick="currentSlide(1)"></span>
<span class="dot" onclick="currentSlide(2)"></span>
<span class="dot" onclick="currentSlide(3)"></span>
</div>
<script src="script.js"></script>
</body>
</html>
for more clarification please download this code : Sample Slider.zip

How dots indicate and manipulate slider with images

I'm trying to build active dots for my slider and I found some reference on w3schools but I don't understand the logic behind the function that controls the dots. Anyone can explain to me how they work into the code below?
To mention: I know how the slider works ,but i don't understand how dots works!
var slideIndex = 1;
showSlides(slideIndex);
// Next/previous controls
function plusSlides(n) {
showSlides(slideIndex += n);
}
// Thumbnail image controls
function currentSlide(n) {
showSlides(slideIndex = n);
}
function showSlides(n) {
var i;
var slides = document.getElementsByClassName("mySlides");
var dots = document.getElementsByClassName("dot");
if (n > slides.length) {slideIndex = 1}
if (n < 1) {slideIndex = slides.length}
for (i = 0; i < slides.length; i++) {
slides[i].style.display = "none";
}
for (i = 0; i < dots.length; i++) {
dots[i].className = dots[i].className.replace(" active", "");
}
slides[slideIndex-1].style.display = "block";
dots[slideIndex-1].className += " active";
}
* {box-sizing:border-box}
/* Slideshow container */
.slideshow-container {
max-width: 1000px;
position: relative;
margin: auto;
}
/* Hide the images by default */
.mySlides {
display: none;
}
/* Next & previous buttons */
.prev, .next {
cursor: pointer;
position: absolute;
top: 50%;
width: auto;
margin-top: -22px;
padding: 16px;
color: white;
font-weight: bold;
font-size: 18px;
transition: 0.6s ease;
border-radius: 0 3px 3px 0;
user-select: none;
}
/* Position the "next button" to the right */
.next {
right: 0;
border-radius: 3px 0 0 3px;
}
/* On hover, add a black background color with a little bit see-through */
.prev:hover, .next:hover {
background-color: rgba(0,0,0,0.8);
}
/* Caption text */
.text {
color: #f2f2f2;
font-size: 15px;
padding: 8px 12px;
position: absolute;
bottom: 8px;
width: 100%;
text-align: center;
}
/* Number text (1/3 etc) */
.numbertext {
color: #f2f2f2;
font-size: 12px;
padding: 8px 12px;
position: absolute;
top: 0;
}
/* The dots/bullets/indicators */
.dot {
cursor: pointer;
height: 15px;
width: 15px;
margin: 0 2px;
background-color: #bbb;
border-radius: 50%;
display: inline-block;
transition: background-color 0.6s ease;
}
.active, .dot:hover {
background-color: #717171;
}
/* Fading animation */
.fade {
-webkit-animation-name: fade;
-webkit-animation-duration: 1.5s;
animation-name: fade;
animation-duration: 1.5s;
}
#-webkit-keyframes fade {
from {opacity: .4}
to {opacity: 1}
}
#keyframes fade {
from {opacity: .4}
to {opacity: 1}
}
<!-- Slideshow container -->
<div class="slideshow-container">
<!-- Full-width images with number and caption text -->
<div class="mySlides fade">
<div class="numbertext">1 / 3</div>
<img src="img1.jpg" style="width:100%">
<div class="text">Caption Text</div>
</div>
<div class="mySlides fade">
<div class="numbertext">2 / 3</div>
<img src="img2.jpg" style="width:100%">
<div class="text">Caption Two</div>
</div>
<div class="mySlides fade">
<div class="numbertext">3 / 3</div>
<img src="img3.jpg" style="width:100%">
<div class="text">Caption Three</div>
</div>
<!-- Next and previous buttons -->
<a class="prev" onclick="plusSlides(-1)">❮</a>
<a class="next" onclick="plusSlides(1)">❯</a>
</div>
<br>
<!-- The dots/circles -->
<div style="text-align:center">
<span class="dot" onclick="currentSlide(1)"></span>
<span class="dot" onclick="currentSlide(2)"></span>
<span class="dot" onclick="currentSlide(3)"></span>
</div>
When one of the dots are clicked the method currentSlide is called with a corresponding parameter. The method showSlides is then called (with the same parameter) which does the following:
saves the collection of elements with class name mySlides and dot into
two variables:
var slides = document.getElementsByClassName("mySlides");
var dots = document.getElementsByClassName("dot");
For more info:
getElementsByClassName() Documentation
if the passed parameter is bigger or smaller than the number of slides (if for example more dots exists than slides), then the index of the slide that will be displayed is set to value in order to still display a slide
if (n > slides.length) {slideIndex = 1}
if (n < 1) {slideIndex =slides.length}
the value of property display is set to none for each slide
for (i = 0; i < slides.length; i++) {
slides[i].style.display = "none";
}
For more info:
Style display Property Documentation
CSS display Property Documentation
class active is removed from all dots
for (i = 0; i < dots.length; i++) {
dots[i].className = dots[i].className.replace(" active", "");
}
value of property display is set to block for the corresponding slide
slides[slideIndex-1].style.display = "block";
class active is added to the clicked dot
dots[slideIndex-1].className += " active";
I hope this is enough :)

How to fix pure JavaScript slider code so it moves the screen?

I want to move the slide when I press the button on the slide. But I can not.
Changing the button's css to active was successful, but when I pressed the button, it continued to fail to move the screen.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
*{margin:0; padding: 0;}
li{list-style: none;}
.dots{width:20px; height: 20px; border-radius: 50%; background-color: #124412;}
.active{width:20px; height: 20px; border-radius: 50%;background-color: #fff;}
#slide{}
#slide ul
#slide ul li{}
.container{width: 900px; margin: 0 auto;}
</style>
</head>
<body>
<div id="slide_wrap">
<div class="container">
<div id="slide">
<ul>
<li><img src="slideimg/1.jpg" alt="1"></li>
<li><img src="slideimg/2.jpg" alt="2"></li>
<li><img src="slideimg/3.jpg" alt="3"></li>
<li><img src="slideimg/4.jpg" alt="4"></li>
<li><img src="slideimg/5.jpg" alt="5"></li>
</ul>
</div>
<div id="dot">
</div>
<div id="arrow">
<div id="left-arrow">left</div>
<div id="right-arrow">right</div>
</div>
</div>
</div>
<script>
var width = 640;
var height = 480;
var length = document.querySelectorAll('#slide li').length;
var slide = document.querySelector('#slide');
var slideUl = document.querySelector('#slide ul');
var slideLi = document.querySelectorAll('#slide li');
slide.style.width = width + "px";
slide.style.height = height + "px";
slide.style.overflow = "hidden";
slideUl.style.width = width*length +"px";
for(var i=0; i < slideLi.length; i++){
var item = slideLi.item(i);
item.style.width = width + "px";
item.style.height = height + "px";
item.style.cssFloat = "left";
}
var dot = document.getElementById('dot');
for(var i = 0; i < slideLi.length; i++){
var btn = document.createElement('button');
btn.classList.add('dots');
dot.appendChild(btn);
//btn.setAttribute('onclick','moveTo('+i+')');
}
var dots = document.querySelectorAll('.dots');
function moveTo(index){
index = index || 0;
index = index % length;
slideUl.style.marginLeft = "-"+width*index+"px";
for(var i = index ; i < dots.length ; i++){
for(var j = 0; j < dots.length ; j++){
if(dots[j].classList.contains('active')){
dots[j].classList.remove('active');
}
}
dots[index].classList.add('active');
}
}
for(var i = 0 ; i < dots.length ; i++){
dots[i].addEventListener('click', function(e){
for(var j = 0 ; j < dots.length ; j++){
if(dots[j].classList.contains('active')){
dots[j].classList.remove('active');
}
e.target.classList.add('active').moveTo(i);
}
})
}
var index = 0;
//left
function slideLeft(){
slideUl.style.marginLeft = "-"+width*(index-1)+"px";
index--;
}
//left click
var arrowLeft = document.getElementById('left-arrow');
arrowLeft.addEventListener('click', function(){
console.log(index)
if(index === 0){
index = slideLi.length;
}
slideLeft();
});
//right
function slideRight(){
slideUl.style.marginLeft = "-"+width*index+"px";
index++;
}
//right click
var arrowLeft = document.getElementById('right-arrow');
arrowLeft.addEventListener('click', function(){
console.log(index)
if(index === length){
index = 0;
}
slideRight();
});
var currentIndex = 0;
setInterval(function(){
currentIndex += 1;
moveTo(currentIndex)
},1000 * 1.5);
moveTo(0)
</script>
</body>
</html>
Slider
var slideIndex = 1;
showSlides(slideIndex);
function plusSlides(n) {
showSlides(slideIndex += n);
}
function currentSlide(n) {
showSlides(slideIndex = n);
}
function showSlides(n) {
var i;
var slides = document.getElementsByClassName("mySlides");
var dots = document.getElementsByClassName("dot");
if (n > slides.length) {slideIndex = 1}
if (n < 1) {slideIndex = slides.length}
for (i = 0; i < slides.length; i++) {
slides[i].style.display = "none";
}
for (i = 0; i < dots.length; i++) {
dots[i].className = dots[i].className.replace(" active", "");
}
slides[slideIndex-1].style.display = "block";
dots[slideIndex-1].className += " active";
}
* {box-sizing: border-box}
body {font-family: Verdana, sans-serif; margin:0}
.mySlides {display: none}
img {vertical-align: middle;}
/* Slideshow container */
.slideshow-container {
max-width: 1000px;
position: relative;
margin: auto;
}
/* Next & previous buttons */
.prev, .next {
cursor: pointer;
position: absolute;
top: 50%;
width: auto;
padding: 16px;
margin-top: -22px;
color: white;
font-weight: bold;
font-size: 18px;
transition: 0.6s ease;
border-radius: 0 3px 3px 0;
user-select: none;
}
/* Position the "next button" to the right */
.next {
right: 0;
border-radius: 3px 0 0 3px;
}
/* On hover, add a black background color with a little bit see-through */
.prev:hover, .next:hover {
background-color: rgba(0,0,0,0.8);
}
/* Caption text */
.text {
color: #f2f2f2;
font-size: 15px;
padding: 8px 12px;
position: absolute;
bottom: 8px;
width: 100%;
text-align: center;
}
/* Number text (1/3 etc) */
.numbertext {
color: #f2f2f2;
font-size: 12px;
padding: 8px 12px;
position: absolute;
top: 0;
}
/* The dots/bullets/indicators */
.dot {
cursor: pointer;
height: 15px;
width: 15px;
margin: 0 2px;
background-color: #bbb;
border-radius: 50%;
display: inline-block;
transition: background-color 0.6s ease;
}
.active, .dot:hover {
background-color: #717171;
}
/* Fading animation */
.fade {
-webkit-animation-name: fade;
-webkit-animation-duration: 1.5s;
animation-name: fade;
animation-duration: 1.5s;
}
#-webkit-keyframes fade {
from {opacity: .4}
to {opacity: 1}
}
#keyframes fade {
from {opacity: .4}
to {opacity: 1}
}
/* On smaller screens, decrease text size */
#media only screen and (max-width: 300px) {
.prev, .next,.text {font-size: 11px}
}
<div class="slideshow-container">
<div class="mySlides fade">
<div class="numbertext">1 / 3</div>
<img src="https://images.pexels.com/photos/248797/pexels-photo-248797.jpeg" style="width:100%">
<div class="text">Caption Text</div>
</div>
<div class="mySlides fade">
<div class="numbertext">2 / 3</div>
<img src="https://images.pexels.com/photos/459225/pexels-photo-459225.jpeg" style="width:100%">
<div class="text">Caption Two</div>
</div>
<div class="mySlides fade">
<div class="numbertext">3 / 3</div>
<img src="https://images.pexels.com/photos/33109/fall-autumn-red-season.jpg" style="width:100%">
<div class="text">Caption Three</div>
</div>
<a class="prev" onclick="plusSlides(-1)">❮</a>
<a class="next" onclick="plusSlides(1)">❯</a>
</div>
<br>
<div style="text-align:center">
<span class="dot" onclick="currentSlide(1)"></span>
<span class="dot" onclick="currentSlide(2)"></span>
<span class="dot" onclick="currentSlide(3)"></span>
</div>
Get More : https://www.w3schools.com/howto/howto_js_slideshow.asp

Disabling/hiding slideshow arrows on first/last slides

I am using a slideshow based on w3school's sample. I'd like to disable or hide the previous arrow on the first slide and next arrow on the last slide.
I believe I need to edit this JavaScript to include an if else clause (if first slide, hide .prev button, else show), but the problem is my lack of understanding. I have a basic understanding of JavaScript, but going deep into the math side (n or i values) is confusing me, and I haven't yet learned jQuery.
function plusSlides(n) {
showSlides(slideIndex += n);
}
Can anyone help me with the code, and also explain what the code would mean in layman's terms?
For easy reference, the code pulled straight from the example is:
var slideIndex = 1;
showSlides(slideIndex);
function plusSlides(n) {
showSlides(slideIndex += n);
}
function currentSlide(n) {
showSlides(slideIndex = n);
}
function showSlides(n) {
var i;
var slides = document.getElementsByClassName("mySlides");
var dots = document.getElementsByClassName("dot");
if (n > slides.length) {slideIndex = 1}
if (n < 1) {slideIndex = slides.length}
for (i = 0; i < slides.length; i++) {
slides[i].style.display = "none";
}
for (i = 0; i < dots.length; i++) {
dots[i].className = dots[i].className.replace(" active", "");
}
slides[slideIndex-1].style.display = "block";
dots[slideIndex-1].className += " active";
}
/* Slideshow container */
.slideshow-container {
max-width: 1000px;
position: relative;
margin: auto;
}
/* Next & previous buttons */
.prev, .next {
cursor: pointer;
position: absolute;
top: 50%;
width: auto;
margin-top: -22px;
padding: 16px;
color: white;
font-weight: bold;
font-size: 18px;
transition: 0.6s ease;
border-radius: 0 3px 3px 0;
}
/* Position the "next button" to the right */
.next {
right: 0;
border-radius: 3px 0 0 3px;
}
/* On hover, add a black background color with a little bit see-through */
.prev:hover, .next:hover {
background-color: rgba(0,0,0,0.8);
}
/* Caption text */
.text {
color: #f2f2f2;
font-size: 15px;
padding: 8px 12px;
position: absolute;
bottom: 8px;
width: 100%;
text-align: center;
}
/* Number text (1/3 etc) */
.numbertext {
color: #f2f2f2;
font-size: 12px;
padding: 8px 12px;
position: absolute;
top: 0;
}
/* The dots/bullets/indicators */
.dot {
cursor:pointer;
height: 13px;
width: 13px;
margin: 0 2px;
background-color: #bbb;
border-radius: 50%;
display: inline-block;
transition: background-color 0.6s ease;
}
.active, .dot:hover {
background-color: #717171;
}
/* Fading animation */
.fade {
-webkit-animation-name: fade;
-webkit-animation-duration: 1.5s;
animation-name: fade;
animation-duration: 1.5s;
}
#-webkit-keyframes fade {
from {opacity: .4}
to {opacity: 1}
}
#keyframes fade {
from {opacity: .4}
to {opacity: 1}
}
<div class="slideshow-container">
<div class="mySlides fade">
<div class="numbertext">1 / 3</div>
<img src="img1.jpg" style="width:100%">
<div class="text">Caption Text</div>
</div>
<div class="mySlides fade">
<div class="numbertext">2 / 3</div>
<img src="img2.jpg" style="width:100%">
<div class="text">Caption Two</div>
</div>
<div class="mySlides fade">
<div class="numbertext">3 / 3</div>
<img src="img3.jpg" style="width:100%">
<div class="text">Caption Three</div>
</div>
<a class="prev" onclick="plusSlides(-1)">❮</a>
<a class="next" onclick="plusSlides(1)">❯</a>
</div>
<br>
<div style="text-align:center">
<span class="dot" onclick="currentSlide(1)"></span>
<span class="dot" onclick="currentSlide(2)"></span>
<span class="dot" onclick="currentSlide(3)"></span>
</div>
I'm not quite sure what part of the code you need an explanation for. In general terms it's just adding or substracting from the slide index, adjusting the index when it "overflows" or "underflows" and hiding the slides with a different index.
If you don't want to show first and last arrows you can just add code like
var prevArrow = document.getElementsByClassName('prev');
var nextArrow = document.getElementsByClassName('next');
prevArrow[0].style.display = "block";
nextArrow[0].style.display = "block";
if (slideIndex === 1) prevArrow[0].style.display = "none";
if (slideIndex === slides.length) nextArrow[0].style.display = "none";
That code just "hides" the "prev arrow when you're in the first slide and the "next" arrow when you're in the last", you can test it in the w3school page and it works. I hope that helps
There's a lot of room for optimization

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