Develop Reference

why doesn't off canvas code work in mobile?

I got this code from https://www.w3schools.com/howto/tryit.asp?filename=tryhow_js_sidenav and it works fine in mobile as is. So simple, yet effective. But my usage doesn't work in my mobile or my customer's mobile.
console says:
(index):66 Uncaught TypeError: Cannot read properties of null (reading 'style')
at openNav ((index):66)
at HTMLDivElement.onmouseover ((index):79)
Would anyone like to hazard a guess as to why this doesn't work?
function openNav() {
document.getElementById("mySidenav").style.width = "250px";
}
function closeNav() {
document.getElementById("mySidenav").style.width = "0";
}
.sidenav {
height: 100%;
width: 0;
position: fixed;
z-index: 1;
top: 0;
left: 0;
background-color: #96AD74;
background-color: #9C836E;
overflow-x: hidden;
transition: 0.5s;
padding-top: 30px;
letter-spacing: 1px;
}
.sidenav a {
padding: 8px 8px 8px 32px;
text-decoration: none;
font-size: 25px;
color: #E2FAC0;
display: block;
transition: 0.3s;
text-shadow: 1px 1px 0 #000;
}
.sidenav a:hover {
color: darkblue;
background: #808000;
background: #7E6EB5;
background: #FFAC1C;
text-shadow: none;
}
.sidenav .closebtn {
position: absolute;
top: 0;
right: 25px;
font-size: 36px;
margin-left: 50px;
text-shadow: none;
}
#main {
transition: margin-left .5s;
padding: 16px;
}
#media screen and (max-height: 450px) {
.sidenav {
padding-top: 15px;
}
.sidenav a {
font-size: 18px;
}
<div id="mySidenav" class="sidenav" onmouseleave="closeNav();">
<div class="pcc">MENU</div>
home
coaching
biography
contact
</div>

If I understand correctly, you want to close the menu when the user touches anything outside of it on a phone.
Add the following to your JavaScript file:
document.addEventListener('click', function(e) {
var mySidenav = document.getElementById("mySidenav");
var openButton = document.getElementById("openButton");
if (mySidenav.style.width == "250px" && !mySidenav.contains(e.target) && e.target != openButton) {
closeNav();
}
});
This will make it so when you click (touch) on any element besides the open button, it will close the sidebar.
Also, don't forget to set the ID of the element opening the navbar to "openButton", for example in the W3School tutorial you linked, you should modify it like this:
<span id="openButton" style="font-size:30px;cursor:pointer" onclick="openNav()">☰ open</span>

Some hr tags have gaps inside them while other doesn't

I have a pen, which is basically a todo app. The todo items are actually li elements which have text, button and a hr. Some of them are having hr with spaces inside them while some doesn't.
Image:
HTML:
const j = $;
j(() => {
let validify = txt => {
if (txt.length > 0) {
j('#ctn').append(`<li class='td'>${txt}<button class='td-btn'>Dismiss</button><hr/></li>`);
}
j('.td-btn').on('mouseenter', function() {
console.log('added');
j(this)
.parent()
.addClass('del');
console.log(j(this).parent().attr('class'))
}).on('mouseleave', function() {
console.log('removed')
j(this)
.parent()
.removeClass('del');
}).on('click', function() {
j(this).parent().css('display', 'none');
});
j('#addtd').val('');
}
validify('');
j('#btn').on('click', () => {
validify(j('#addtd').val());
});
});
#import url("https://fonts.googleapis.com/css?family=Lato");
* {
box-sizing: border-box;
font-family: Lato;
}
body {
margin: 0;
padding: 3vh 7vw;
background: #004D40;
}
#in-ctn {
position: fixed;
width: 86vw;
height: 16vh;
background: #388E3C;
box-shadow: 0 6px 9px #272727;
z-index: 2;
}
#btn {
position: absolute;
border-radius: 100%;
outline: none;
border: none;
right: 7vh;
top: 3vh;
width: 10vh;
height: 10vh;
font: 500 8vh arial;
display: inline-block;
transition: 0.25s all;
background: #CDDC39;
}
#btn:hover {
box-shadow: 0 2px 1px rgba(0, 0, 0, 0.33);
transform: scale(1.1);
}
#btn:active {
transform: translateY(4px);
}
#addtd {
position: absolute;
outline: none;
border: none;
background: rgba(255, 255, 255, 0.33);
width: 50vw;
height: 6vh;
top: 5vh;
left: 5vw;
font: 500 14pt Lato;
padding: 0 10px;
}
#addtd::placeholder {
color: #FFF;
}
#ctn {
position: absolute;
top: 27vh;
width: 86vw;
background: #388E3C;
box-shadow: 0 6px 9px #272727;
padding: 3vh 5vw;
z-index: 1;
}
li.td {
font: 500 20pt Lato;
list-style: none;
color: #FFF;
}
button.td-btn {
float: right;
outline: none;
border: none;
background: #E53935;
height: 20px;
position: relative;
top: 25px;
color: #FFF;
}
hr {
border: 7px solid #9E9D24;
padding: 0;
}
.del {
color: #CDDC39 !important;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id='main'>
<div id='in-ctn'>
<button id='btn'>+</button>
<input type='text' id='addtd' placeholder='Enter a new Todo' />
</div>
<div id='ctn'>
<li class='td'>
Code a Todo App
<button class='td-btn'>Dismiss</button>
<hr/>
</li>
<li class='td'>
Style the Elements
<button class='td-btn'>Dismiss</button>
<hr/>
</li>
<li class='td'>
Debug some problems
<button class='td-btn'>Dismiss</button>
<hr/>
</li>
<li class='td'>
Go for a walk
<button class='td-btn'>Dismiss</button>
<hr/>
</li>
</div>
</div>
Can anyone explain me why it is so?

This is happening due to CSS Sub pixel rendering.
When you zoom-in/out of the browser, the rescaled elements will have left over pixel values like 5.75px etc. The vendor decides how to deal with that.
In your case the easiest fix, at least in Chrome, is to cancel the border radius to 0px, instead set the height of the hr to double the border and give it a background color:
border: 0px solid #9E9D24;
padding: 0;
height: 14px;
background: #9E9D24;

Seems like this issue is browser related, since it works fine for most people. Possibly your browser has a default styling for hr elements. It is, however, nowadays bad practice to use a horizontal line for presentational terms. Source
You would be fine by using a border-bottom on your li element. If you want to position the border lower than the default position, you can use padding-bottom on the li element. Your HTML structure also looks a lot more clear with this.
For example, changing the styling of your CSS selector li.td to the following could do the trick:
li.td {
font: 500 20pt Lato;
list-style: none;
color: #CDDC39;
border-bottom: 10px solid #9E9D24;
padding-bottom: 10px;
margin-bottom: 10px;
}
In case you really need to use the hr element, you could attempt to remove all default margin since some browsers add a margin by default. For that, add the following styling to the element:
margin: 0
which would result into
hr {
border: 7px solid #9E9D24;
padding: 0;
margin: 0;
}

Did you edit your pen to fix the issue? When looking at your pen preview all <hr> tags are rendered without an empty space inside.
The only suggestion I have, is that in HTML <hr> doesn't need to be explicitly closed, unless you are using XHTML, then you need to properly close the tag <hr />. Since you are just writing HTML, I would go with the <hr>.

Sidebar navigation toggle with single button

I have implemented the following sidebar navigation into a simple admin. I've got it working and moved to the right side. I would like to have it appear and disappear using a single button rather than a separate close and open button. I tried modifying the JS with an onToggle function that if isOpen was null, it would open the panel and then set isOpen to true and then the next time it ran, it would delete isOpen. I'm very new at JS and this failed so I thought I'd ask here. How do I get this puppy appearing and disappearing with a single button?
http://www.w3schools.com/howto/tryit.asp?filename=tryhow_js_sidenav
Thank you kindly.

<!DOCTYPE html>
<html>
<style>
body {
font-family: "Lato", sans-serif;
}
.sidenav {
height: 100%;
width: 0;
position: fixed;
z-index: 1;
top: 60px;
left: 0;
background-color: #111;
overflow-x: hidden;
transition: 0.5s;
padding-top: 60px;
}
.sidenav a {
padding: 8px 8px 8px 32px;
text-decoration: none;
font-size: 25px;
color: #818181;
display: block;
transition: 0.3s
}
.sidenav a:hover, .offcanvas a:focus{
color: #f1f1f1;
}
.closebtn {
position: absolute;
top: 0;
right: 25px;
font-size: 36px !important;
margin-left: 50px;
}
#media screen and (max-height: 450px) {
.sidenav {padding-top: 15px;}
.sidenav a {font-size: 18px;}
}
</style>
<body>
<span style="font-size:30px;cursor:pointer" onclick="openNav()">☰ open</span>
<div id="mySidenav" class="sidenav">
×
About
Services
Clients
Contact
</div>
<h2>Animated Sidenav Example</h2>
<p>Click on the element below to open the side navigation menu.</p>
<script>
function openNav() {
var e = document.getElementById("mySidenav");
if (e.style.width == '250px')
{
e.style.width = '0px';
}
else
{
e.style.width = '250px';
}
}
function closeNav() {
document.getElementById("mySidenav").style.width = "0";
}
</script>
</body>
</html>
This is the same code with little modifications in the openNav() method. For triggering the sideNavbar with a button, it needs to be visible before and after triggering the sideNavBar. So i have moved the view button to the top and i have modified the top property of sidenav to keep the trigger button visible even after activation
You can view this in action here: https://jsfiddle.net/ngohrvk1/

I know the question is tagged with JavaScript and you probably don't want to change the markup or add new elements. But if you could, here's a pure CSS solution that works.
body {
margin: 0;
}
.sidebar-toggle {
position: absolute;
left: 0;
top: 0;
z-index: 2;
padding: 10px;
background: red;
color: white;
}
#sidebar-toggle-input {
display: none;
}
#sidebar-toggle-input+label:before {
content: "➡️";
}
#sidebar-toggle-input:checked + label:before {
content: "❌"
}
.sidebar {
position: fixed;
width: 200px;
transition: 0.3s;
background: blue;
height: 100vh;
top: 0;
left: 0;
transform: translateX(-100%);
}
#sidebar-toggle-input:checked ~ .sidebar {
transform: none;
}
<input type="checkbox" id="sidebar-toggle-input" />
<label class="sidebar-toggle" for="sidebar-toggle-input"></label>
<div class="sidebar"></div>

This code will help you out, I have created a function and saving data-isshown attribute on the element, to get whether the element is shown or not, we can decide this on the basis of the width as well but this is more generic approach
function toggleNav() {
var element = document.getElementById("mySidenav")
var shown = element.getAttribute("data-isshown");
if (shown == "true") {
element.setAttribute("data-isshown", "false");
element.style.width = "0";
} else {
element.setAttribute("data-isshown", "true");
element.style.width = "250px";
}
}
Whole code would look like this
function toggleNav() {
var element = document.getElementById("mySidenav")
var shown = element.getAttribute("data-isshown");
if (shown == "true") {
element.setAttribute("data-isshown", "false");
element.style.width = "0";
} else {
element.setAttribute("data-isshown", "true");
element.style.width = "250px";
}
}
body {
font-family: "Lato", sans-serif;
}
.sidenav {
height: 100%;
width: 0;
position: fixed;
z-index: 1;
top: 0;
left: 0;
background-color: #111;
overflow-x: hidden;
transition: 0.5s;
padding-top: 60px;
}
.sidenav a {
padding: 8px 8px 8px 32px;
text-decoration: none;
font-size: 25px;
color: #818181;
display: block;
transition: 0.3s
}
.sidenav a:hover,
.offcanvas a:focus {
color: #f1f1f1;
}
.closebtn {
position: absolute;
top: 0;
right: 25px;
font-size: 36px !important;
margin-left: 50px;
}
#media screen and (max-height: 450px) {
.sidenav {
padding-top: 15px;
}
.sidenav a {
font-size: 18px;
}
}
<div id="mySidenav" class="sidenav">
×
About
Services
Clients
Contact
</div>
<h2>Animated Sidenav Example</h2>
<p>Click on the element below to open the side navigation menu.</p>
<span style="font-size:30px;cursor:pointer" onclick="toggleNav()">☰ open</span>

how to slowly show element in vanilla js? My main concern is to show this element slowly

$(".warning").show("slow");
body {
background: #2d3339
}
.warning {
border: 5px solid #e1dfbe;
width: 200px;
margin: 100px auto 20px;
border-radius: 5px;
padding: 20px 10px;
text-align: center;
font-size: 32px;
display: none;
}
.warning span {
color: #f4f3ce;
font-family: sans-serif;
font-weight: bold;
}
.image {
position: absolute;
top: 20%;
width: 100%;
text-align: center;
z-index: -1
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<p class="warning">
<span>Lorem ips</span>
</p>
how to write $(".className").show("slow") in vanilla js? My main concern is to show this element slowly.
like this in jquery

Do you want some kind of fade effect? You can try doing something with CSS transitions to change the opacity. Take a look at this JSFiddle. You can make it slower/faster by changing the amount of time the transition takes.
HTML:
<p id="my-para">Hello, my name is John</p>
<button id="btn">Show Element</button>
CSS:
p {
opacity: 0;
}
.fade-in {
opacity: 1;
transition: opacity .9s ease;
}
JS:
var btn = document.getElementById('btn');
btn.addEventListener('click', function() {
document.getElementById('my-para').classList.add('fade-in');
});

show and hide menu with jquery

I would like,when clicking on the menu icon change to an X shape with animation and when clicking on X shape it change to menu icon.
I write this part.I have problem with clicking function. at first when I click on the menu button it change to X shape and show the menu but when I want to close menu my js codes does not work and I don't know why this happening.
I used bootstrap in my codes
I upload my site here
html
<div class="col-xs-6">
<a class="bazar" href="">دانلود اپلیکیشن </a>
<button type="button" style="z-index:401" class="navbar-toggle try-op" >
<span style="z-index:401" class="icon-bar top-m"></span>
<span style="z-index:401" class="icon-bar mid-m"></span>
<span style="z-index:401" class="icon-bar bottom-m"></span>
</button>
<div class="menu"> <!-- <span class="btnClose">×</span> -->
<ul>
<li>صفحه اصلی</li>
<li>سوالات متداول</li>
<li>فرصت های شغلی</li>
<li>درباره ما</li>
</ul>
</div>
</div>
js
$('.try-op').click(function() {
$('.navbar-toggle').removeClass('try-op');
$('.navbar-toggle').addClass('texting');
$('.top-m').addClass('top-animate');
$('.mid-m').addClass('mid-animate');
$('.bottom-m').addClass('bottom-animate');
$('.menu').addClass('opened');
var height = $( window ).height();
$('.menu').css('height',height);
});
$('.texting').click(function() {
$('.navbar-toggle').removeClass('texting');
$('.menu').removeClass('opened');
$('.top-m').removeClass('top-animate');
$('.mid-m').removeClass('mid-animate');
$('.bottom-m').removeClass('bottom-animate');
$('.navbar-toggle').addClass('try-op');
});
css
.icon-bar{
transition: 0.6s ease;
transition-timing-function: cubic-bezier(.75, 0, .29, 1.01);
}
.top-animate {
background: #fff !important;
top: 13px !important;
-webkit-transform: rotate(43deg);
transform: rotate(43deg);
transform-origin: 7% 100%;
-webkit-transform-origin: 7% 100%;
}
.mid-animate {
opacity: 0;
}
.bottom-animate {
background: #fff !important;
top: 13px !important;
-webkit-transform: rotate(-221deg);
transform: rotate(-221deg);
transform-origin: 45% 18%;
-webkit-transform-origin: 45% 18%;
margin-top: 0px !important;
}
.bazar-green, .bazar {
color: #fff;
display: block;
font-size: 20px;
position: absolute;
right: 80px;
top: 5px;
line-height: 43px;
background: url(image/bazarlogo.png) no-repeat left center;
padding-left: 80px;
z-index: 401;
}
.navbar-toggle {
display: block;
position: absolute;
right: 0px;
top: 0px;
}
.navbar-toggle{
float: right;
padding: 9px 10px;
margin-top: 8px;
margin-right: 15px;
margin-bottom: 8px;
background-color: transparent;
background-image: none;
border: 1px solid transparent;
border-radius: 4px;
}
.navbar-toggle .icon-bar {
background-color: #fff;
}
.navbar-toggle .icon-bar {
display: block;
width: 22px;
height: 2px;
border-radius: 1px;
}
.menu {
width: 300px;
position: absolute;
z-index: 400;
background: rgba(0,0,0,0.7);
padding: 10px 30px;
text-align: right;
color: #fff;
font-size: 17px;
transition: all 1s;
right: -316px;
}
.btnClose {
color: #fff;
font-size: 30px;
cursor: pointer;
z-index: 500;
}

You are effectively adding 2 click handlers to the same element. When you click on the span elements the second handler is executed, and as the click event propagates then the first click handler is executed.
You should change the logic. Instead of using addClass/removeClass and having 2 handlers you can use just 1 click handler and toggle the classNames using toggleClass method.
$('.try-op').click(function() {
var isOpened = $('.menu').toggleClass('opened').hasClass('opened');
if ( isOpened ) {
// the menu is opened
} else {
// ...
}
});
Another option that you have is using the event delegation technique. I see that you are removing the className in your first handler, probably in order to unbind the handler for the next click handling, but event handlers are bound to elements not to their classNames.
$(document).on('click', '.navbar-toggle.open', function() {
$(this).removeClass('open').addClass('close');
// ...
});
$(document).on('click', '.navbar-toggle.close', function() {
$(this).removeClass('close').addClass('open');
// ...
});

Use $('.navbar-toggle').click(function() {
instead of $('.navbar-toggle span').click(function() {