Develop Reference

updating function when nav link is clicked

Hello I have a feature where when you click a link in the navigation the content of the body switches and I was combining it with a little script from this question and it works great. The only thing is that if you click a link and don't scroll the images won't show up unless you scroll at least 1px. So I was wondering if there's a fix for this. JSFiddle.
Side question: Would it be possible to wait for the content to show up until the page is fully scrolled up?
Script:
$(window).on("load",function() {
function fade(pageLoad) {
var windowTop=$(window).scrollTop(), windowBottom=windowTop+$(window).innerHeight();
var min=0, max=1, threshold=0.01;
$(".fade").each(function() {
/* Check the location of each desired element */
var objectHeight=$(this).outerHeight(), objectTop=$(this).offset().top, objectBottom=$(this).offset().top+objectHeight;
/* Fade element in/out based on its visible percentage */
if (objectTop < windowTop) {
if (objectBottom > windowTop) {$(this).fadeTo(0,min+((max-min)*((objectBottom-windowTop)/objectHeight)));}
else if ($(this).css("opacity")>=min+threshold || pageLoad) {$(this).fadeTo(0,min);}
} else if (objectBottom > windowBottom) {
if (objectTop < windowBottom) {$(this).fadeTo(0,min+((max-min)*((windowBottom-objectTop)/objectHeight)));}
else if ($(this).css("opacity")>=min+threshold || pageLoad) {$(this).fadeTo(0,min);}
} else if ($(this).css("opacity")<=max-threshold || pageLoad) {$(this).fadeTo(0,max);}
});
} fade(true); //fade elements on page-load
$(window).scroll(function(){fade(false);}); //fade elements on scroll
});

You can achieve it by taking fade method outside the load event listener that will make it available everywhere. And then call it from on the click of nav buttons.
See the js below:
$(window).on("load",function() {
this.fade(true); //fade elements on page-load
$(window).scroll(function(){this.fade(false);}); //fade elements on scroll
});
//Take below fade method outside of the load event listener.
function fade(pageLoad) {
var windowTop=$(window).scrollTop(), windowBottom=windowTop+$(window).innerHeight();
var min=0, max=1, threshold=0.01;
$(".fade").each(function() {
/* Check the location of each desired element */
var objectHeight=$(this).outerHeight(), objectTop=$(this).offset().top, objectBottom=$(this).offset().top+objectHeight;
/* Fade element in/out based on its visible percentage */
if (objectTop < windowTop) {
if (objectBottom > windowTop) {$(this).fadeTo(0,min+((max-min)*((objectBottom-windowTop)/objectHeight)));}
else if ($(this).css("opacity")>=min+threshold || pageLoad) {$(this).fadeTo(0,min);}
} else if (objectBottom > windowBottom) {
if (objectTop < windowBottom) {$(this).fadeTo(0,min+((max-min)*((windowBottom-objectTop)/objectHeight)));}
else if ($(this).css("opacity")>=min+threshold || pageLoad) {$(this).fadeTo(0,min);}
} else if ($(this).css("opacity")<=max-threshold || pageLoad) {$(this).fadeTo(0,max);}
});
}
// change activenav class, show the clicked element only and hide the others https://codepen.io/MohdHussein/pen/MWKEvdp
// grab all the buttons
let Buttons = document.querySelectorAll(".selectSection button");
// loop through the buttons using for..of
for (let button of Buttons) {
// listen for a click event
button.addEventListener('click', (e) => {
// et = event target
const et = e.target;
// slect activenav class
const activenav = document.querySelector(".activenav");
// check for the button that has activenav class and remove it
if (activenav) {
activenav.classList.remove("activenav");
}
// add activenav class to the clicked element
et.classList.add("activenav");
// select all classes with the name content
let allContent = document.querySelectorAll('.contentsec');
// loop through all content classes
for (let contentsec of allContent) {
// display the content if the class has the same data-attribute as the button
if (contentsec.getAttribute('data-number') === button.getAttribute('data-number')) {
contentsec.style.display = "block";
}
// if it's not equal then hide it.
else {
contentsec.style.display = "none";
}
}
this.fade(true); //Call fade method on click
});
}
You can test it here.

Web accessible navigation

I'm stuck while implementing drop down for each individual list item on focus/hover on any of them, now on hovering over any single list item all dropdowns are getting displayed.
This is my pen: https://codepen.io/apeandme/pen/GRZOxJQ
and the JS:
// main navigation interaction
'use strict';
var navbar;
var triggerContainer;
var triggerLink;
var toggleButton;
var lastMenuItem;
var mouseOutTimer; // timer used to delay hiding of menu after mouse leaves
var mouseOutHideDelay = 0; // time (in ms) before menu is closed after mouse leaves
var menuVisible = false;
var i = 0;
window.addEventListener('DOMContentLoaded', function(e) {
navbar = document.querySelector('nav');
triggerContainer = document.querySelectorAll('nav > ul > li.with-dd');
triggerLink = document.querySelectorAll('nav > ul > li.with-dd > a');
toggleButton = document.querySelectorAll('nav > ul > li.with-dd > .toggle-button');
lastMenuItem = document.querySelectorAll('nav > ul > li.with-dd > ul > li:last-of-type > a');
// Show the menu on mouse hover of the trigger
triggerContainer.forEach(item => {
item.addEventListener('mouseover', function(e) {
showMenu();
clearTimeout(mouseOutTimer);
});
});
// Hide the menu when mouse hover leaves both the trigger and menu fly-out, but only after a short delay to help people jerky mouse movements (like those using head/eye trackers)
triggerContainer.forEach(item => {
item.addEventListener('mouseout', function(e) {
mouseOutTimer = setTimeout(function() {
hideMenu();
}, mouseOutHideDelay);
});
});
// Hide the menu when the user tabs out of it
triggerContainer.forEach(item => {
item.addEventListener('keydown', triggerKeydownHandler);
});
// Toggle the menu when the trigger is activated
toggleButton.forEach(item => {
item.addEventListener('click', toggleMenu);
});
// Close the menu when the user activates something outside the navbar.
document.body.addEventListener('click', handleBodyClick);
});
/**
Menu visibility
**/
function showMenu() {
triggerLink.forEach(item => {
item.setAttribute('aria-expanded', true);
});
toggleButton.forEach(item => {
item.setAttribute('aria-expanded', true);
});
menuVisible = true;
}
function hideMenu() {
triggerLink.forEach(item => {
item.setAttribute('aria-expanded', false);
});
toggleButton.forEach(item => {
item.setAttribute('aria-expanded', false);
});
menuVisible = false;
}
function toggleMenu() {
if (menuVisible) {
hideMenu();
} else {
showMenu();
}
}
/**
Event handlers
*/
function handleBodyClick(e) {
if (!navbar.contains(e.target)) {
hideMenu();
}
}
function triggerKeydownHandler(e) {
// Hide the menu a keyboard user tabs out of it or presses Escape
if ((e.key === 'Tab' && !e.shiftKey && e.target === lastMenuItem) || e.key == 'Escape') {
hideMenu();
// Move focus back to the menu toggle button if Escape was pressed
if (e.key == 'Escape') {
toggleButton.focus();
}
}
}

Instead of opening all the dropdowns at once when one is hovered, you need to pass the 'hover' event to the function, in order to know which one of the triggers were hovered :
triggerContainer.forEach((item) => {
item.addEventListener("mouseover", function (event) { // catch the 'hover' event
showMenu(event); // pass the event to your function
clearTimeout(mouseOutTimer);
});
});
function showMenu(event) {
event.target.setAttribute("aria-expanded", true); // know which element whas hovered
event.target.nextElementSibling.setAttribute("aria-expanded", true); // open the corresponding dropdown
menuVisible = true;
}

Thanks for the help. Have changed the code , for both showMenu and hideMenu and for mouseover and mouseout events, now individual drop downs are showing on hovering over single menu item, but the dropdowns are hiding soon enough I'm reaching to the last menu item inside the dropdown. Am I missing anything and currently this error is in the console whenever hovering over the last menu item inside the drop-down-
Uncaught TypeError: Cannot read property 'setAttribute' of null
at hideMenu (main.js:68)
at main.js:38
//main navigation interaction
"use strict";
var navbar;
var triggerContainer;
var triggerLink;
var toggleButton;
var lastMenuItem;
var mouseOutTimer; // timer used to delay hiding of menu after mouse leaves
var mouseOutHideDelay = 1000; // time (in ms) before menu is closed after mouse leaves
var menuVisible = false;
window.addEventListener("DOMContentLoaded", function (e) {
navbar = document.querySelector("nav");
triggerContainer = document.querySelectorAll("nav > ul > li.with-dd");
triggerLink = document.querySelectorAll("nav > ul > li.with-dd > a");
toggleButton = document.querySelectorAll(
"nav > ul > li.with-dd > .toggle-button"
);
lastMenuItem = document.querySelectorAll(
"nav > ul > li.with-dd > ul > li:last-of-type > a"
);
// Show the menu on mouse hover of the trigger
triggerContainer.forEach((item) => {
item.addEventListener("mouseover", function (e) {
showMenu(e);
clearTimeout(mouseOutTimer);
});
});
// Hide the menu when mouse hover leaves both the trigger and menu fly-out, but only after a short delay to help people jerky mouse movements (like those using head/eye trackers)
triggerContainer.forEach((item) => {
item.addEventListener("mouseout", function (e) {
mouseOutTimer = setTimeout(function () {
hideMenu(e);
}, mouseOutHideDelay);
});
});
// Hide the menu when the user tabs out of it
triggerContainer.forEach((item) => {
item.addEventListener("keydown", triggerKeydownHandler);
});
// Toggle the menu when the trigger is activated
toggleButton.forEach((item) => {
item.addEventListener("click", toggleMenu);
});
// Close the menu when the user activates something outside the navbar.
document.body.addEventListener("click", handleBodyClick);
});
/**
Menu visibility
**/
function showMenu(e) {
e.target.setAttribute("aria-expanded", true);
e.target.nextElementSibling.setAttribute("aria-expanded", true);
menuVisible = true;
}
function hideMenu(e) {
e.target.setAttribute("aria-expanded", false);
e.target.nextElementSibling.setAttribute("aria-expanded", false);
menuVisible = false;
}
function toggleMenu() {
if (menuVisible) {
hideMenu(e);
} else {
showMenu(e);
}
}
/**
Event handlers
*/
function handleBodyClick(e) {
if (!navbar.contains(e.target)) {
hideMenu();
}
}
function triggerKeydownHandler(e) {
// Hide the menu a keyboard user tabs out of it or presses Escape
if (
(e.key === "Tab" && !e.shiftKey && e.target === lastMenuItem) ||
e.key == "Escape"
) {
hideMenu();
// Move focus back to the menu toggle button if Escape was pressed
if (e.key == "Escape") {
toggleButton.focus();
}
}
}

How to catch clicks on multiple images?

I have an iOS uiwebview with multiple imagemaps that I need to catch clicks on, so I can handle scaling on different iOS devices. The click handler I install works on the first image, but not on subsequent images. How do I make the click handler work on multiple images? The relevant code is below:
$.fn.imageMapSetup2 = function () {
$('img').each(function () {
if (typeof ($(this).attr('usemap')) == 'undefined') {
return;
}
var img = $(this);
// add click handler
img.on('click', function (event) {
img.imgClick(event);
});
});
};
$.fn.imgClick = function (mouseDown) {
mouseDown.preventDefault();
var $img = this;
var map = $img.attr('usemap').replace('#', '');
$('map[name="' + map + '"]').find('area').each(function () {
var $this = $(this),
coords = $this.attr('coords').split(',');
// lots of scaling code omitted
if (mouseX >= left && mouseX <= right &&
mouseY >= top && mouseY <= bottom) {
window.location = $this.attr('href');
}
});
};
FYI I have debugged the code in Safari and function imgClick() is not getting called for the second and subsequent images.

Add a click event listener to the parent element of the images. This could be the body element. Pass the event as an argument. Then, check the event, and use that variable to make changes to your image.
document.addEventListener("click", function (event) {
if (!event.target.tagName === "img") return;
if (typeof event.target.getAttribute("usemap") == "undefined") {
return;
}
imgClick(event);
});

Detecting click on window scrollbar

I'm trying to pause the main window scroll when scrolling a table, which I've done but are having trouble enabling the main window scroll again after.
This function will pause the main window scroll when scrolling over table.
function preventWindowScroll() {
scrollTable = document.querySelector(".members-data");
if (scrollTable.contains(event.target)) {
var oldScrollPos = document.body.scrollTop;
window.onscroll = function () { window.scrollTo(0, oldScrollPos); };
} else {
// disable scrollTo in order to reenable main window pause
window.onscroll = function () {};
}
}
The problem is that if I try to scroll down by clicking and dragging the main window scrollbar it's still jammed by scrollTo.
I've tried doing an onclick event, but it doesn't work when clicking scrollbar.
document.body.onclick = function(e) {
scrollTable = document.querySelector(".members-data");
if (!scrollTable.contains(e.target)) {
window.onscroll = function () {};
}
};
I've also tried removing the event listener, but can't figure out where to put it.
document.body.removeEventListener('mousewheel', preventWindowScroll);
document.body.removeEventListener('DOMMouseScroll', preventWindowScroll);
If I could just detect when a user clicks on the main window scroll eit would work as intended.
note: I have achieved pausing the main window scroll other ways, but they all have slight drawbacks.
Thanks

I use this code. Works in Chrome.
yourTable.addEventListener('wheel', handleMouseScroll);
function handleMouseScroll(e) {
var delta = e.deltaY || e.detail || e.wheelDelta;
if (delta < 0 && this.scrollTop == 0) {
e.preventDefault();
}
if (delta > 0 && this.scrollHeight - this.clientHeight - this.scrollTop <= 1) {
e.preventDefault();
}
}

Identify mouse events during requestPointerLock

Is there any way to identify right click event ("contextmenu") & scroll events while pointer lock API is enabled? I am trying to create a browser-based 3d game in which the player will be able to perform different activities by left clicking, right clicking, middle clicking and scrolling - while pointer is locked.
index.html
<body><button id="lock">Start game</button</body>
app.js
$("#lock").on("click", function(e) {
lockPointer(); // invokes the requestPointerLock API
e.stopPropagation();
});
// this works perfectly
$("body").on("click", function(e) {
// do stuff on left click
});
// this does not work
$("body").on("contextmenu", function(e) {
// do stuff on right click
});

For right click you can use mousedown or mouseup event, it works with requestPointerLock
$('body').on('mousedown', function(e) {
if (e.which === 1) {
// left button
} else if (e.which === 2) {
// middle button
} else if (e.which === 3) {
// right button
}
});
For scrolling you can use wheel event:
$('body').on('wheel', function(e) {
var dx = e.originalEvent.deltaX;
var dy = e.originalEvent.deltaY;
if (dy < 0) {
// scroll up
} else if (dy > 0) {
// scroll down
}
if (dx < 0) {
// scroll left (some mice support this)
} else if (dx > 0) {
// scroll right (some mice support this)
}
});